I don’t know about “normal”, but I’d argue it’s pervasive.

We seem to associate certain behaviours and patterns with categories of identity, and changing those behaviours in yourself implies an acceptance of that “other” identity.

I remember this distinctly about 20 years ago when I thought about not eating meat anymore. Choosing not to eat meat was easy, but “becoming a vegetarian” felt alien, and took some mental effort. I didn’t see myself as “one of those” people.

I suspect it has a lot to do with how important group identity is to us, as social primates, and how we tend to package one behaviour with a bunch of others. It’s like doing pushups will suddenly make you a “jock” (and maybe the irony is that, to a certain degree it will, as these thing tend to turn into slippery slopes).

The irony is that, at least in my social circles, the stereotype of the "software developer who does rock-climbing" is really a thing.

To the point where, because part of my identity is being a hipster who is not like everyone else, I tend to avoid rock-climbing unless it's with friends, and when people ask me what sports I do I tell them I do Olympic Weightlifting, because it's actually somewhat original, even if, in practice 90% of the people at my Oly lifting club are either sports coaches or engineers :P