I used to count steps when I was a kid. As I got older, I counted them in other languages. Now I wear a pedometer (a fitbit, actually) so that every step is counted but I don't have to pay attention to them...

I also count birds. But that's because I like watching them, and by counting them I learn more about them. I got into the habit of doing it and now it's automatic.

I used to calculate powers of two in my head when I got bored on the line in the restaurant kitchen... I'm a bit of a numbers geek, though.