Suffice it to say, I didn’t spontaneously decide to run in a perfectly straight line across Grant and Millennium Parks. Here’s the run I actually did:

I see a few possibilities right off the bat:

1. My pace is so blazingly fast that no GPS device can accurately track me.
2. RunKeeper is terrible.
3. AT&T service in Chicago is terrible.

Guess which one of these is most likely.

Update: Same run, different day, worse result. Much worse. This time, I apparently decided to change course and run into the lake for a quick dip, then curve around through buildings until I ended up two blocks west of my building. Yep.