When navigating through column view in Finder, at times your destination folder gets exactly aligned to the left (thus hiding the parent folder out of the visibile view).
If you need to quickly switch to the parent directory without scrolling or hitting the left arrow key, just click in the white space at the bottom of your current folder and Finder takes you to the parent folder.
It's small things like this that make OS X a pleasure to use.
[crarko adds: This is one of those things I think has been around a long time, but it's nice to see reminders sometimes.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20120108081031565