people always act so crazy they make fun of people thwey laugh then they act like theyb are so good so why do people act so stupid
No one does anything because they think it's a bad idea or that it's a stupid thing to do. They always have some underlying reason or belief that they should, even if it's without much thought.
So, to them, they aren't acting stupid, just being themselves. That means they are either stupid to start with or that they acted impulsively, the latter of which draws more questions about themselves.