What's the most insignificant thing someone's hurt your feelings over?

The other day, I was showing my mom how a friend of mine writes the letter "q" oddly.

She said "that looks just as horrible as putting a line through a 7."

I said, "But... I put lines through my 7's."

She looked at me, frowned, and said "I know."

Don't know why, but it completely crushed me, and I was in a bad mood the rest of the day.

Also, when I was younger, I was writing something on the computer and my dad was in the same room. He said "Gosh, you're gonna need a fire extinguisher before long if you keep typing that fast". I know it was a joking compliment, but it made me incredibly self-conscious about my typing speed (I wasn't even that good back then. I can't have been typing more than 30 or 40 WPM)