Why do people say things that aren't true?

[Anonymous]

Like, I'm talking about people saying mean things. Like saying someone is whatever. Like today someone called me lazy when I know I am one of the hardest workers I know. But I've been called a ton of rude or mean words for so long, and I want to know why people say them. I've never done that because I don't really gain anything from it, and when I was younger, a friend of mine told me after I made a slightly mean joke in 3rd grade. He said, "Don't say that because how would you feel if someone said that about you", that stuck, and if I want to make a joke or say something, I think, "no, if someone said that to me, I'd be upset." I mean I've messed up here and there and said maybe one or 2 mean things, but that's really only to siblings because I think unreasonably hard before I speak in public.

[Guy13]

We are fallen and sinful so we do bad things like lie…

[Asker]

Yeah but like maybe because when I get mad or annoyed I go in lockdown mode and I either don't speak or if I am at work and I get mad I'll talk very limited like only to customers and only few words. But like don't people do the "treat people how I want to be treated" saying in life? Like I know, i am not perfect by being nice all the time, I just rarely say any insults out loud