What has Dan Seifert done to his 5S?

On multiple occasions he's said how Touch ID on the 5S is garbage, how it barely works for him. Weird, I was skeptical about the finger print sensor initially, but I forget it's even there now due to how incredibly quick, seamless and effective it is. We all got issued them at work, and I don't know a single person who doesn't think it's great. Faulty iPhone maybe?