Appreciate your health. You're alive, you're kicking! If you want to improve the vessel you're living in (your body) then you can. Eat clean foods. Exercise. Quit smoking. Lay off boozing. Get sleep. Treat yourself right. Your body is your home.
Appreciate your home. Sounds silly, right? But think of those without homes. They have nowhere to go to sleep, to unwind, to eat, to bathe. Be happy you can do all of these things in a place that's familiar and all yours.
Appreciate your family and friends. Sure, they can drive you crazy sometimes, but they love you and you love them. They're supportive and only have the best wishes for you. If anyone is dragging you down, then let them go, and appreciate that you're strong enough to do so.
Appreciate your independence. Be happy that you are an individual who can make you own choices, whether it's what you order for dinner or what you pursue for your career or who you marry. You have a great deal of freedom and that is sometimes hard to come by.
Also, appreciate the little things...
The hugs. The crappy TV shows you love. The treat meals. The workouts. The sunsets. The sunrises. The favorite pair of sweats you own. The puppy kisses. The hand-holding. The books. The texts. The laughs. The nights in. The board games. The home-cooked meals. The un-chipped nail polish. The good hair day. The beanie to hide a bad hair day. The cup of tea. The vase of flowers.