15% vs 20%

Having met my flash of brilliance quota for the day, I spent the rest of the afternoon in meetings and calculating the difference in my paycheck if I deposited 15% of my salary towards my 401K versus 20%. After taxes and insurance, the difference came down to 85 dollars per paycheck. Is it bad that I'm thinking about retirement already?

edit: Today really feels like Friday, for some reason. Maybe it was the catered lunch, or the nice weather outside. In any case, I hope I don't forget to come in to work tomorrow. Like Dwight Schrute.