I'm not gonna vouch as I don't feel I spend enough time with you to appropriately gauge if you have changed or not. I will give you some advice though no matter if you get accepted or not.
It's normal to lose your cool occasionally, I still to this day sometimes get overly mad at things that I shouldn't be, just take a quick breath and read what you're gonna say a few times before you post it or just think about what you're gonna say if you think it might cause some problems.
At the end of the day, bickering with people is not worth it if you can't let go, don't hold grudges and just try to enjoy your time with your fellow members/friends.
Try to be more empathetic, think to yourself "What if I was in their shoes and had to deal with someone like me, am I acting reasonable?"
I wish you the best of luck in your application.