Things that make you Crabby!

[Pamela]

Mosquito bites.

Not sure if it's already been mentioned, but I won't bother reading 13 pages to find out. =p

Getting multiple mosquito bites and feeling like a freaking bloodbank.
That nice stain on the wall where you smashed it,or a spider.*depends on how big the spider IS...grab the flyswatter...or scream for help*
A mosquito bite under a thumbnail.
That itches like crazy,but you can.t scratch it.
People wondering why on earth you are toying with your thumb.
Then point and laugh at you.
Reminding them that they are A)Either naturally repellent to said insect....or B) their blood just tastses nasty to said insect.