Regret is a subjective feeling, not always related to validity or usefulness. A better question could be what pitfalls to avoid when becoming a programmer, or when choosing a career path, etc.

The question may also suffer from sampling bias:

-Is a programmer and does not regret it (represented)

-Is a programmer and regrets it (represented, less likely to respond)

-Is not a programmer and does not regret it (not represented)

-Is not a programmer and regrets it (not represented)