I feel like this all the time. I often screw up and make little mistakes, so then I get angry because I just want to do things right. Im often un inspired with a lot of things. When I get inspiration I have to go with it right away.
I often feel this way after I meet someone new for the first time. I try to make a good impression and be outgoing and stuff, but I always seem to fall short because I can never think of things to say because I put way too much pressure on myself. Then I get disappointed in myself that stuff like that doesn't come naturally to me like it should.
A big example is when I talk to my crushes and then walk away thinking: "What the hell was I doing!?" Or when I fail a test.
Or today when I let the dripper in my chameleon's cage run too long and got water all over my desk, had to take the poor guy out of the cage, make him mad, clean the water, put him back and move his stuff around. :C I feel bad about it and I'm quite ashamed that I didn't realize how fast the water dripped out, lol.
Normally I get disappointed with myself after making a bad impression though.