Anything that might excite you will make the day go by quicker. I know when my wife makes my favorite dinner (meatloaf for one) it puts me in a good mood and I can't wait to get home! Two weeks ago I thought I might have a few hours alone at home and the thought of buying some padding - any kind - was really exciting for a few days. But the plans fell through.
I think contentment (from any source) gives you more energy and drive, and if you've felt happy and fulfilled doing things in your little headspace, you're likely to carry an extra spring in your step whilst going about your daily duties. It's as simple as that, really.
I remember when I first got my bottle in college I decided to have little time and use it and I was refreshed when I woke up in the morning and I was wide awake for my 8 AM class. I didn't even remember falling asleep that night.