If were talking the little unheralded things in life, like taking off your shoes at the end of a long day, rather than the essentials, like tea, then...
Going to the loo when you really, really have to go.
The first whiff of a sea breeze when you go to the seaside.
The sky. Especially those sunsets which look like they've been painted on silk or those times where the light's just right and it feels as if you could scoop out the air.
The smell of freshly cut grass on a hot summers day.
Making someone laugh unexpectedly.
Seeing my niece/nephew really enjoy or understand/realise something.
That moment when you finally remember something you've been trying to remember for ages.
Coming up with an answer in a quiz out of nowhere when no one else had a clue.
The relief of finishing something and knowing you're as far away from having to do it again as you'll ever be.
Realising 'you're in'.

Your own bed after being away.
Noticing a pattern or sequence that's completely meaningless (such as 1:23am or the odometer of a car turning over to a 'big number' or a face in wood grain)
Refracted light. Especially through a prism.