"Biology may or may not care about the physicist's insatiable desire for elegance." -- Jeff Hasty
Figure 1: In other words, sometimes this happens. From Hasty et al, Physical Review Letters 2002 | doi:10.1103/PhysRevLett.88.148101
2. Another lesson that is just as serious
Humor in lab is essential, of course. However, if you just heard the great story about the giant biohazard bag full of innocuous things in your PI's car... finish laughing before you load your gel.
The idea, of course, is to prevent this from happening. [Original photo source]