Simple things; in no particular order:
Rediscovering something you've forgotten, such as old music, art, a book or an old friend.
Having a home that is spotlessly clean.
Being able to wake up naturally, and not have the alarm clock do it.
Driving out to the country with the windows/top down, the sunroof open, and the stereo on full blast.
The same, with just the wind for company.
Kitties and doggies. Especially the Headbutts from the cat.
The smell of a good, hard, soaking rain before it begins.
Learning something new.
Soft, crisp freshly laundered sheets.
That first really crisp and cold fall evening.
A wood fire.