Don't read your work e-mail after 6:00 pm or 10 minutes before you plan on leaving, whichever comes first.
Because if you do, you might read a frantic e-mail about a problem with hot project and even though it's not your project and you don't even know if the information is available anywhere, you might still feel compelled to help fix the problem.
Luckily (or maybe not), one of the two people who had the information was available so between the two of us, the problem was solved. Teamwork, yeah! And as soon as the information was sent, we shut down our computers and went home. Any more problems can wait until tomorrow. And do you think anyone will appreciate what we did? I don't think so. Good thing we take pride in our work. Even if it meant getting home at 7:45 pm.