Used to get ingrown toenails on my big toes, they'd get infected and turn green and ous would come out. Had to have a GP cut and remove the inside of the toenail on each foot. The needle straight down the center of the toe to numb it was absolutely killer.
Otherwise my annoying one; I bite my finger nails and sometimes tear the nail off too far back, meaning I end up with a really sore and painful finger that I can't put pressure on.
Also as I get older just general stretching / pulling / throwing out of muscles etc. Seriously, I never believed it when I was younger that you could hurt yourself doing anything mundane, and if you did it healed in a day or two at most. Now I'm older and far less active everything physical is a chore. I got a 2ltr bottle of drink out the fridge the other week and it must habe gone through all the incorrect motions to do so because it threw my back out. It took over a week to heal : / yeh, just getting a drink out of the fridge. Fuck getting older. What are my 40's and 50's going to be like if it's already like this?