Stepping on a piece of lego with bare feet. Full force.
Having a mosquito bite in an unreachable place.
Cutting too much into your nails.
Painful hanging skin right at kabbolos Shabbos- another 24 hours to go!
Pouring spoiled milk into the last teaspoon of coffee you have in the house.
Nicking an already nicked area when shaving.
Having a neighbor who sings chazzanus off key.