I like the commit streak statistic because, when I attempt to maintain a long streak, I get into the habit of committing something - even something small - once a day. Once I've made even the slightest change, I'm more likely to keep working. I find that it's a good motivator.

"Don't break the chain!" http://lifehacker.com/281626/jerry-seinfelds-productivity-se...

It's totally superficial, but I find it fun. It's something to check once in a while and be like "hey, I have a dark green box. I wonder how many times I committed that day."

When I left my previous job, they revoked my Github access and I lost 3k commits on the calendar and it was a bummer. I wasn't throwing a fit or anything. I just had to start over :).