I do? I mean, I don't consider myself an unusual athlete or anything. But if I'm biking or lifting, I almost always have a smile on my face, even while pushing myself. So do other people I know, so I really don't think it's unusual.
Even if it isn't something one does without being prompted, frame of mind is such an important part of performance. Anything that can lower perceived effort is worth taking seriously.
"How are you?"