Having a positive attitude causes you to have a better outlook on life and on your quest to be healthier. By posting positive notes around the house, you are continuing to surround yourself with positivity. I post my notes around my bedroom and on my bathroom mirror each day of something happy. These are two places that I go to for refuge when I may be having a rough day. Reading the notes helps me to take a look and see what I should be thankful for and to begin back on the right track.
Having others post notes of positive thoughts of you, your friendship, etc. also gives you a chance to stay positive and motivated.