I've quit a multi-year smoking habit.

I'm not saying it is easy, but re-programming your thinking by interrogating your assumptions is very much possible (and essentially the core mechanic in cognitive behavioral therapy).

It's also important to note that if I examine how you think, that basically does nothing. You need to do it yourself, earnestly, if it's to have an effect.

Hmm, I think there's more to it than you mention, then. It sounded in the first comment a bit like "I thought about it and I quit", but I guess there's more intention/reflection (and more often) than that?

Can you go into the details a bit more? It sounds interesting.