You shouldn’t tell people to kill themselves, even if you’re joking, because someone might. Plus it makes you sound like an abusive asshole, in the same way that using “gay” as a slur makes you sound like a homophobic asshole. If that’s the pony you’d like to hitch your wagon to, sure okay, but don’t fucking pretend you don’t understand why “You should kill yourself” is a monumentally shitty thing to say.
This is why no one likes you.