The funniest thing I ever observed, actually, was at a college level summer league game. I was the unofficial coach for our college alumni team in the league and during one of our games, the opposing team's coach crossed half court and coached his team in
our coaching box.
I figured I'd return the favor and the host school's coach (who also refreed a majority of the games) told me to get back in my box. I told him that was fine, but he better tell the other coach to stop tap-dancing his way into my box.
He did say something to the opposing coach because the opposing coach gave me a very dirty look afterwards. I either smiled at him or shrugged my shoulders.