I find myself a bit upset by people waiting at airports with the names of passengers on a piece of card (even if they're, like, a chauffeur); people sleeping on buses with signs saying 'Wake me up at [whatever stop]' around their necks; untouched buffets, bake sales or craft stalls; and most bizzarely, serious_cat's journal.
Please to be making me feel less of a freak. :)
ETA: I don't mean things that irritate you. I mean things that make you sad or emotional. It worries me a bit that people seem to assume that by "upset you" I meant "piss you off" - I might be a bitch, but not enough of a bitch to get pissed off about unbought brownies!
ETA2!: I thought of another one which really takes the cake - those penpal websites for prisoners on death row. Even though they're fucking murderers, all that blurb about how lonely and friendless they are reduces me to a pulp. Ridiculous.