Pretty much any Arnie quote, in fact, anything, as long as it's completely out of context, or just the yells that he does

haha
I also sometimes say "You despise me!" as it annoys my sister, as once we had an argument when we were kids and the whole family were there.
And it went completely quiet, and she said it with such conviction, like it was her magnum opus of put downs.
It just made everyone laugh

haha