stapling a sticky note 

Used to describe someone taking joy in doing extra work that will make little or no difference (a sticky note should stick to a surface by itself, but some add a staple to it just to make sure it does not).

Your brother was stapling a sticky note when he made a second batch of pasta even when he knew the first batch was more than enough.

stapling a sticky note by Brother's Third Wheel May 3, 2018