Of course a good, long playlist of my personal jams with a beer next to me :)
But reasons to actually get to work:

1. If it's an interesting task and everything goes according to plan, I get a positive feedback loop of motivation.
2. Deadlines.
3. Personal projects are always easier for me to begin with and stay focused on.

Personal projects are also dangerous for me because I keep going back to them until I don't have any motivation to go back to my work projects... Kinda like a double edged sword I guess