Be an economist again, without the girlfriend in grad school (who never became the wife in any case cos I thankfully dumped her before the job market). I probably lost one or two decent papers. The sex was good but she was dumb and didn't like it when I discussed stuff way over her head with others. Cramped my style.
I would've made sure to focus more on the real stuff, life work, good friends, and good experiences. All the other distractions that didn't last the past decade were a complete waste of time.