I agree about sometimes feeling like a CSI when trying to track down performance issues or particularly nasty bugs. For some reason, I actually enjoy going through log files step by step trying to figure out what bizarre condition has triggered all hell to break loose.
Of course, that just emphasises the importance of proper logging, especially in large complex systems. It's not easy to isolate the problem if you don't have the 'evidence' to find out what might be causing it.