I am not a neat guy. I tend to drop coffee cups on my desk and I never look back. What I learned this year is that if you leave a cup of cappucino for a week on your desk, then drink a shot of it by mistake while staring at your computer screen, you are left with a terrible taste in your mouth for the rest of the day. However, day-old cappucinos are ok.
There is a lesson here kids: do not leave projects without attention for weeks at a time. You will get a bad taste once you go back to it later.