A couple of decades ago I was young and stupid, I got my kicks out of hollering "on your LEFT" when I passed folks. Occasionally, I'd have to pass someone on the right, and so I'd holler "on your RIGHT." While I was doing a 50-mile organized ride from Rosarito-Ensenata (Mexico) I was feeling pretty awesome and tried to pass between two road-hogging riders. I hollered "on your RIGHT on your LEFT" and made my dash to squeeze between them. Unfortunately, they each looked over their inside shoulders, drifted together, and I ate Mexican pavement at 25mph.

Now I try to pass conservatively, without jackassery. Don't always holler, but always try to take enough room so as to avoid either surprising the other person or have them get in my way.