A colleague once setup a PR description template that asked for short sections like:

- Why is this change needed (big picture)

- Why are you doing it this way (small picture)

- What are the trade-offs you made for this approach

- How do you know this is correct, that it works the way you think it does?

- What other changes or approaches does committing to this way block in the future?

etc. If you had actually thought through what you were doing, it was a few min to fill it all out. People were just on auto-pilot really struggled.