Why am i bad at bullets?

When your system of thinking is based on good principles and is automated, then you become good at bullet.

In bullet games , you have to think fast and move , playing random moves can win you some games at most but as you advance , it won't work with other high rated players so you need to play fast as well as play smart . For this you must take in consideration the given position and play a decent move at least, if not the best in a little amount of time . This can only be developed through practice as your mind needs to get accustomed to process the information and calculate a move quickly . Applying theoretical calculations takes time and thus it is somewhat difficult for beginners but as you play a lot of games , you get a better idea of how to do it . Blitz games provide a bit more time and are a good way to practice your way up .

it is very hard but we have to think fast to win

I recommend you to play rapid games if you want to improve your chess skills, playing bullets won't make you bad at chess but it is not recommended for beginners so just play rapid if you are at a beginner level.

if u wanna get better at bullet defend rather than attack.

if ur a begginer