The possibilities are endless. Remind yourself to get flowers for your mother on Mother’s Day. Never again forget to reserve a restaurant for your anniversary. Get that Angry Bird’s toys for your kid’s birthday. Persuade yourself to quit your boring job and do what you always wanted to do but keeps hesitating like climbing Mount Everest or swimming in Antarctica. Buy milk at the store next Monday because you are running out of milk.
OR Just send a message to your five years future self with “Dear Me, why am I still using this ancient phone? Please get a new and better one. Sincerely, Myself.”