Bugs are irritating. However the feeling once you solved a big one.... so amazing. Makes being a software engineer really worth it :D
Just yesterday, I solved a mystery in an app I develop for a customer. The app ran everywhere (browsers, Windows, Android), just not on the iPhone. It started up and some code was running, but the damn thing did not budge when I clicked a button to connect to a server. Worst part: ever tried to debug a Cordova App on an iPhone? There just is no way. So I had to add lots of logging and was searching around for two weeks, before I finally solved the bug. Yesterday was the best evening since long :)