Inspiration and indifference + let the manager know about it.

Inspiration.

Cleaning bad code and/or fixing errors is actually one of the things I like the most about software development. It's the easiest thing to do and one of the most educating, specially if it's one's own bad code and/or errors that one's fixing.

That said, like all good things, it's better in moderation. If I were doing it all day I'd go crazy.

1- Feeling good if coder have same work experience e.g (one year work experience coder mostly use lots if-else statements.) I was also do this.

2- Infinite anger Fu*k this sh*t , If coder write bad code and he/she have rich work experience.

If I'm in the area of code I need to change, I'll change it. If I'm just following code and happen upon something I think could be done better, I'll probably leave it alone if it's not broken, but make a mental note that it needs to be refactored.

Usually I get really mad. Mainly because it is ME that will have to fix and refactor something that could have been done right in the first place.

-- Hey, why don't we work on this great new feature that could bring value to the project?

-- Can't. We are rewriting the bad software we wrote a while ago.