Whenever I did something stupid in the past, I immediately got angry. I used to curse and shout from time to time until I tried a different approach. I hated it when I got angry, and while I got angry I additionally got angry at myself for getting angry.... so you see why this turned out to be a problem.
The new approach I tried was very simple:
Pretend you did it on purpose!
You rip a bag of pasta by accident and they spill all over the floor - pretend you did it on purpose! Tell yourself that you always wanted to find out how far they could spill after being ripped open and now you know! You open the fridge and your incense-ashtray spills all over the food - pretend you did it on purpose! Tell yourself that you got tired of eating clean food all the time and you tried this to spicen up your dinners. The sheer idiocy and abstruseness of your explanations will make you laugh in an instant, and nobody can stay mad, while they're laughing.
This already made me laugh billions of times and it turned some bad days into good ones. Maybe it's useful for you guys as well.