It makes a lot of sense to commit always to the smallest possible ‘meaningful’ amount of work on a project and count every little bit extra as exactly that: a bonus. If you have a bad day - or 14 …or 500 - you may still be able to do the thing without feeling bad that it wasn’t more you did. Works equally will for habits. Feeling good about the small amount you did is better than feeling bad about the small amount you did.