What does it take to be a programmer, not just to become one?

Making peace with the fact that there will never be a day when perfect code springs full formed from your head like a Greek goddes, and that what you are getting paid to do (assuming you're getting paid) is to be aggravated.

If the job is good, the aggravations are the kind that you get to have fun eliminating: clients with use cases the product team didn't think of, someone changed an API and didn't tell you, you need to build a new feature, etc. (If the job is bad, the aggravations are probably the same as any other bad job: meetings or mismanagement.)