In no particular order:
Holding and smelling a newborn baby
Nursing a newborn baby, or even a toddler. You'll never be emotionally closer to an other human being any other way.
The feeling after a big party at your house is over and everybody has gone home, and you and your immediate family just melt into the couch and chairs, with candles burning and cake and cookies on the table and just.... sit! *sigh*
The bliss after an amazing orgasm, and blazing hot sex, just lying in his arms and drifting off to sleep. Or getting energized by it and just hanging out and loving.
Taking off down the road on a road trip, knowing you'll have no responsibilities for a week or so.
Having a few days off after a long row of daily shifts and not having to get up the next morning. Ahhh...