Did you know there’s a wrong way and a right way to use a post-it?
If you peel them off the pack upwards from the bottom corner, they tend to just curl up and fall off the wall – especially with modern paints which seem to be chemically engineered to repel anything. I noticed half my retros were ending up on the floor and I spent a lot of time picking up pesky post-its and slamming them back up on the wall, only to watch them fall again. I was like that clown at the circus, running from spinning plate to plate, trying to keep them all in the air. Then someone showed me the right way – peel them off the pack sideways to avoid adding any curl. Your post-its will stay stuck much longer.
Bart Vermijlen explains it really well here: http://www.bartvermijlen.com/how-to-peel-of-a-sticky-note/