LifeHacker has a good list of the tricks your brain can play on you that cause you to behave differntly than you would want to normally. Here's the top 2 from the list:
2. You Value New Numbers Based on Other, Unimportant Numbers
Why do infomercial hosts insist on telling you what "you'd expect to pay" for any item they're about to price? Because the "Anchoring Effect" works. A salesman tells you that the golf clubs you're looking at cost $1,200, you scoff, and suddenly he's noting that, this week, they're on sale for $599. Your brain remembers the first number, it sets the second number against it, and it looks like you'd be stupid not to pick up this deal—no matter how ridiculous the first price. Photo by bradleygee. (Original post)
1. You Let Negative Feelings About Putting Off Tasks Prevent Actual Work
Could sending out that email really be so painful that you've put it off three days in a row? Likely not, but it certainly feels that way every time you try to dig in. It's what a Psychology Today post describes as the "overwhelming wave" of negative emotions, building and seemingly towering over you when you try and address yourself to a task. Knowing that it's really this kind of meta-misery, though, you can perhaps acknowledge it, let it go, then move on.
Image from biologycorner on flickr