In support of your claim, I have never gouged myself with my toothbrush.
When you put it like that I understand why many of your are pushing automatic success. But I didn't think we were talking about skill challenges that weren't challenging.
I'm saying picking locks should never be an automatic success because the lock pick could break off in the lock.
Swimming across water could be challenging if you're wounded.
Of course brushing your teeth doesn't even merit a skill roll.