The first reason is that you don't speak well, you are always mocking others, and you are always talking about their shortcomings, which makes others embarrassed. People won't like you at this time. Being outspoken is an advantage, but being mean is not outspoken.
The second reason is whether you like to take advantage when dealing with others. If you are selfish and do everything for yourself, then others will stay away from you. Many times, we have to learn to share with others.
The third reason is whether you respect others in the process of interacting with others. For example, interrupting others often will make others feel unhappy and make others think you are rude.
The fourth reason is whether you are always full of negative energy. If you complain about life all day and spread negative energy all day, then of course others don't want to deal with you.