A non comprehensive list of things that make me happy as an adult (in no particular order):
A beautifully roasted, well ground batch of coffee.
Flowers.
Walking into the subway.
Working ATM machines.
Comfortable slip-ons.
Clean floors.
The smell of freshly ground spices.
Falling asleep within ten minutes of going to bed(this hardly happens!).
Ticking things off a to-do list.
Warm lights.
Neatly filed documents.
An organised desktop.
Yellow stationary.
And a new crisp diary to write on!