Problem by @HoonOh

I guess the insult must have been really bad till the point whereby you initiated to stop being friends anymore :(( boys are all the same , they love to joke and play around with everyone , its normal . But if their joke is taken to a whole new level , i think you might wanna have a heart to heart talk with him so he can understand how you feel truly since he probably doesnt think much of his own joke .

Calling you "flat" may come off as a habit from him , and you do know that habits are kinda hard to change and needs loads of time . Give him some time to hopefully change and if he really apologizes sincerely to you , i think you shouldn then forgive him .

However , if hes still being nasty with you and calling you flat to the point whereby you cannot stand it and lowers you self esteem , you should cut him from your life and make better friends .

Best of wishes !!