Going to the gym and doing an exercise at a higher weight than you'd planned simply because it was already on the bar and you're too lazy to change the plates.
The last guy left his plates on the bar after he finished. It's only 10 more pounds than I was going to do and I really don't feel like changing the plates. Fuck it, guess I'm pumping irony today.
A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.