For what it's worth, 35mm for me too.
RWC said it very well - participant and observer.
Being a direct participant makes it all the more rewarding for me, gives me a purpose and a sense of satisfaction.
When I need to go near, I remember the shot. It means a bit more to me.
Going close, I pay more attention to it.
I'm more aware - so the process becomes a little more deliberate instead of simply a random snap.
I think when the two aspects combine, it's even more shiok.
Sometimes you can be really close, but still surreptitious.
You observe the scene and go in close for the kill - best of both worlds.
Observe and participate.
On a more technical note, I like 35mm because it works great in smaller spaces.
The 35 also makes it easier to include some background to the shot, giving it context.
And if I really need to go close, I'd take a few steps forward.
On a more practical note, I use the 35 because it's the only lens I have.
Edit: Bro Newghost, we gotta arrange that test soon - your collection of 35s is killing me!