Why don't they just..?
When I first started in corporate programming and had to pick up on big projects that someone else had left off, I often found myself saying the same thing a lot.  "Man, they did this in such a dumb way.  Why didn't they do it this way?  They must not have been very smart."<p>So I would go in and "fix" things... only to find out a month later that the code was the way it was because of some obscure edge case that I had never thought of.  It turns out that in my arrogance <i>I</i> was the dummy all along.<p>After that happened a couple of times, I stopped approaching strange code with that attitude.  Programmers are in general pretty clever, and if you see something strange in some code, don't assume it's because they're dumb.  At first assume it's because <i>you're</i> dumb, and only change your mind if careful and deliberate analysis--and talking to someone else with history in the organization--proves otherwise.