Things that you really want to be proud of wont be done in one session, however, it would be nice if it was.
Try not to think of it that way, just ignore that. Thinking of it taking long kindof takes away motivation.
Tune out most other things. If something else happens that negatively, or even positively impacts you, you'll want to focus on it.
Also, what Pass said. That's what I do lol.