What is "luck"? (Most Chinese or Asian people believe in "luck")
For the minds that are still under the influence of ignorance and egoism, "bad luck" can be related to something bad, difficult, undesirable and unpleasant, while "good luck" can be related to something good, easy, desirable and pleasant.
In terms of Buddhism and yoga, we can relate this "luck" with karma, or cause and effect. "Good luck" equal to good karma/cause. "Bad luck" equal to bad karma/cause. However, there's neither good nor bad upon the absence of ignorance, where either "good" or "bad" luck/karma/cause that give rise to easy or difficult, pleasant or unpleasant, desirable or undesirable experiences/conditions/situations, are all selfless and impermanent.
We might be aware of we and other people whom we know in our life, are going through different experiences in life. Some agreeable experiences might bring us joy and happiness, and some disagreeable experiences might bring us painful sorrow and unhappiness.
When we experience painful sorrow and unhappiness in life, naturally we will think, "Why do we have such bad experiences even though (we think and believe that) we didn't do anything bad or wrong in life, and have tried to live a righteous life of good thoughts, actions and speech?"
While looking at some other people who didn't do much good deeds and have been doing lots of (what we think and believe as) wrong and evil actions and speech, but then, they are having all the "good, desirable and enjoyable things/experiences/conditions/situations" in life, and that makes us think, "This is so unfair!"
We might think that it must be something to do with "luck" or "karma".
Indeed, it is the law of cause and effect, or karma. Nothing is not karma, or everything is arising and passing away influenced by cause and effect.
If our mind is pure and bright (loving, forgiving, goodwill, generous and cheerful), everything will turn out to be good karma or "good luck" for us. Things, happenings, conditions or situations that seem to be obstacle, difficult, failure, undeserving, unpleasant, undesirable or not good for most people, it is actually good karma or "good luck" for us, and are igniting and helping us to grow and advance in certain way and somehow.
We are the one who creates our own luck (karma). No one can give us or take away our "good luck" or "bad luck" (good karma or bad karma), the seeds or cause that we have planted by ourselves, out of desires, through thoughts, actions and speech.
When we frown at ourselves and frown at other people (being bitter, angry and hating towards ourselves and other people, for some reasons), we are creating "bad luck" for ourselves. If our mind is being in the state of "unpleasantness", full of bitterness, anger and hatred, we are inviting "bad luck" or "unpleasant experiences/conditions/situations" to come into our life. The more we complain about many things, the more "bad luck" will be accumulating in our life.
When we smile at ourselves and other people (being joyful, loving and kind towards ourselves and other people, with or without any specific reason), we are creating "good luck" for ourselves. If our mind is full of joy, love and kindness, unconditionally, our "good luck" will be over flowing and those who come in contact with us will also be sharing our generosity, which is endless and unlimited, or will never be exhausted. Although, it doesn't remove the ignorance and the consequences of ignorance in other people. It cannot change the karma, or cause and effect that is ceaselessly being created by all the others in the world.
The more we give and share without asking anything in return, the more the "good luck" (virtue and merit) will be accumulating in our life, even if we are not craving for any "good luck", or have no attachment or intention to be generating and accumulating any good karma.
If we have been doing lots of good deeds through actions and speech, but our mind is still full of impure thoughts and is over-powered by corrupted thinking and belief, bitterness, anger, hatred, jealousy, greed and lustful desire, then it will be like we are building a beautiful wooden house with "good deeds", but at the same time, we are also inviting lots of termites and pests into the house with "impure thoughts". Just by doing good is not enough, but we also need to stop creating bad karma (all kinds of unpleasantness/ill-will/impurities in the mind), and not just at the physical actions and speech level, but also cultivate openness, generosity, light and purity in the mind.
Be grateful and thankful, stop complaining upon experiencing something that is difficult, unpleasant, undesirable and disagreeable. At the same time, freeing our mind from the desire of craving and aversion, or expectation. Without any intention, we will see the change of "luck" in our life very soon.
Endure or withstand all the bad karma ("bad luck") that are ripen and are happening to us in our life now without aversion or complaint. Let go of the past unhappy happenings, don't let them continuously to haunt us, hurt us, determine us, disturb us, or affect us. We have to take full responsibility for our own past karma that we had created for ourselves through our ignorant impure thoughts, action and speech, whether consciously or unconsciously, whether we remember or don't remember, whether we are aware or unaware.
At the same time, be loving, compassionate and forgiving towards our own self and towards all other beings. Be patient, generous, cheerful, thoughtful, motivational, supportive and uplifting towards ourselves and towards other people either through our thoughts, actions and speech, or any of them, without asking or expecting anything in return, without craving for good karma or "good luck" in return.
And be very patient. A tree needs time and nurturing to grow into a mature state to have flowers and fruit.
Our life will change by itself, by generating good karma and stop creating bad karma, without attaching towards our good deeds, without craving for good karma or aversion towards bad karma.
If we continuously creating bad karma either wittingly or unwittingly, along side with creating good karma, it is like, planting a tree on a piece of dry land with no access to water or nutrients. Or, it is like planting a tree on a piece of land that is polluted by chemicals or there are lots of insects and animals are eating the leaves, or the flowers, or the fruit, even before we manage to harvest the fruit and taste the fruit.
If we are still being unhappy or dissatisfied with our life experiences now, after we have been doing lots of good deeds, then ask ourselves, "Are we really selfless and pure in all our thoughts, actions and speech? As if our mind is selfless and pure, there won't be any unhappiness or dissatisfaction about something arising in our mind."
If our mind is truly selfless and pure, then there shall be no complaints at all, because we will be happy, grateful and thankful for everything as we are (such as being able to sleep, can breath freely, can move the fingers and toes, or can go to the toilet to pee and shit, as there are many people are suffering because they cannot sleep, cannot breath freely, cannot move their fingers and toes, or cannot go to the toilet to pee or shit), and we will appreciate life as it is, not being determined by the undesirable, unpleasant and disagreeable life experiences, and not complaining about the things that we wanted to have, but we couldn't have or didn't have.
We are so much lucky than many people in the world, if we still have the attention and energy to be unhappy and dissatisfied about something. Even if we don't have anything that we want, and have all the things that we don't want, we still have our own Self.
In the end, there is nothing "good" or "bad" when we know the truth of everything, that everything is the manifestation of cause and effect, and everything is just being what it is.
"Illness", "old age", "injury", "accident", "conflict", "separation from the loved ones", "coming in contact with the disagreeable ones", "difficulty", "hardship", "failure", "unhappy experiences", "undesirable experiences", "failure", "obstacle", "non-accomplishment", "ignorance", "death", and etc, they all are not "bad luck" or bad karma. They are not something "bad". They are the manifestations from our past accumulated karma, consciously or unconsciously, out of ignorance and desires. They are just being what it is. They all are subject to selflessness and impermanence, and eventually they all will be passing away. We are the one who had created all these pleasant/unpleasant karma for ourselves (out of ignorance, desires and attachment), and by ourselves, we harvest the fruit of our past deeds. Good or bad, desirable or undesirable, pleasant or unpleasant, painful or enjoyable, it is our own products produced by ourselves.
It seems like a restless loop of continuous selfless cause and effect that doesn't have an end, however, the teachings of buddhism and yoga has the same teaching that "All these can be stopped or ended through the elimination of ignorance and the annihilation of the selfless modification of the mind, or SILENCE."