What Fills Your Heart with Joy?

As a spy, what do you enjoy doing the most? A few things come to mind, but nothing makes me happier than backstabbing a pyro.

I'm not a very good spy so whenever I can get a stab+sap in, I am usually pretty happy.

Backstabbing a fully-charged medic makes me feel warm and frothy inside. Backstabbing other spies is also very satisfying.

backstabing ppl infront of everyone else like a suicide bomber and wait for them to type:

OMG GO TO HELL YOU N00B PEICE OF **** I HOPE YOUR MUM DIES

Heh, getting all my stuff sapped as engy, then going spy and stabbing the sh*t out of them.

either stabbing a really really really annoying sniper or a entire team thats snipers
or running around a base of 102938102983 sentries and dispensers and teleporters and sapping all of them in about 2 seconds. then cloaking and sneaking away and then coming back again as someone else.

spy capping

Seeing another spy going into the cloak, then guessing where he is and getting a backstab on him.

Sapping an engies sg, teleporter, dispenser, and then jumping on his head, and stabbing downward for the kill.

I have yet to pull this off, for that matter, I have yet to find reason to do this.  There's nothing I'd like to do more in tf2 than to steal the intel, take the intel up the long stairs, and to have some1 following directly behind me up the stairs.  I want to crouch jump over and behind the person pursuing me up the stairs and backstab them, going then about my merry way to cap the intel.  If any1's done exactly this, kudos.     

Since I am new to the spy game, getting ANY backstab is worth my time and celebration.