Bullying. My best friend was trying to fit in with the cool kids at the new school but I wasn't, so they decided to bully me. My best friend just watched. The worst thing is that this happened to me again two years later when I switched schools and reunited with my two other friends who didn't study at the same school as the first one.
That was the worst moment in my life, I can't imagine such a thing happening twice over. Especially with my current group of friends, so many good memories would've been shattered if that happened. Way back when, my so-called friends even had the gall to come up to me and apologize for it when the cool kids were not around. But I guess after all these years it really stopped bothering me. We do stupid things when we're younger I suppose.