One of the biggest lessons of life is to know how to say no, and to say "no" when you can't, or you'll be in an awkward situation. For example, some activities are not very important and take valuable time. The worse thing is to be busy with little things. It is worse than doing nothing. You have to say no. To be really careful, it's just that no matter what other people do, you have to prevent others from getting your own business. You have to say no. Don't belong to anything, or you will not belong to yourself. You can't always ask yourself to be satisfied and always meet other people's demands. Otherwise the good will get worse, and you must be temperate, so that you can gain the respect and affection of others. Rejection is valuable because it's not what you're trying to get yourself to be and accept, and learning to refuse makes you easier, and you can always benefit from it.