This applies strongly to the IT industry as well, especially to system administrators. Whenever there's a problem on the network and it simply goes away by itself, it's bound to come back and bite you in the ass later. It is also guaranteed to come back at a time when you won't be able to deal with it easily, like at 3AM on a weekend.

This is why it's important to investigate ALL problems, even the ones that appear briefly and then simply go away. At the very least, find out what caused the problem so you can determine if it's likely to happen again.