I swear some people just don't get that language changes over time and some slang just gets dropped really quickly.
Things people used to say when I was a kid that no one says anymore includes:
Epic
Wicked
Hella
Gay and the r slur as an insult, although some edgelord chuds try to force it back.
Sweet
Noob
l33t
The one comparing feminists to Nazis (thank god this one is gone)
Sick
And many, many more that I've forgotten