People who use grok properly in conversation move up a rung on my opinion-o-ladder.
"to drink"
While the term is firmly established within the jargon (and with good reason, it's a good word to have in the jargon), I have enough distaste for much of Heinlein's work that I don't generally use the term.
I'd have to find some other way to climb your opinion ladder ;)
Wait, not knowing what "grok" means is a "pretty good" filter for a person who is unsuitable for a role as software engineer?