Comments

Avoid.

Comments on a code usually bring more evil than good. Most of the times, a comment about what a variable does, or details of how the things work could:

1. Become outdated, confusing your future self (Yesterday I lost some precious time because of an outdated comment)

2. Could be replaced for some better named variable/function/class.

3. They pollute the code unnecessarily.

It should be clear that avoid != forbid.