Why is everyone so rude..?😿

I was literally in class for 4th period and some girl told me one of her ex best-friends were talking crap about me like in sept and I didn't even know the girl (who was talking mess abt me) and the girl told me that the girl talking about me was also doing it last year because I "Rolled my eyes at her" like girl WHHHATTT?? and the girl telling me was like "But i was watching you and you weren't even looking at her" and when the girl asked why the other girl was talking crap abt me she couldn't even make up a proper excuse...Like girl..I didn't even know her until I sat wiht my group of friends for lunch when school started..😭😞