I love threads like this, they make me immediately want to jump in game and enjoy all the things mentioned! Alas for it being time for work in 10 mins...
I love everything already mentioned.
The fact that this game is open-ended, so could in theory be played forever, and that it allows so many different types of gameplay is just awesome. It is so huge that I don't think I am ever going to discover all aspects of the game or be able to use all build and buy mode items.
There are many, many things they have improved upon since previous versions and I appreciate them very much. Simple things like being able to wear anything during pregnancy, wearing hats with any hair, multitasking, the more natural movements of the sims themselves and the wonderful environments they live in. I do love this game <3