I'm trying to work out what's changed.
Back in Team Fortress Classic, I was all over the spy. Hell, I played under the name KING SPY! such was my delusions of grandeur - and, being such a mediocre spy, they really were delusions. But now, I only really don the Balaclava of Backstabbing when the game dictates our team needs one - an area too packed with turrets to be penetrated with anything short of a medic/heavy-ubercharge-combo, a stalemate in a narrow area with all the teams facing a single point, whatever. I do the job with surgical precision and then get the hell out.
Why don't I love the Spy anymore? What's changed?
After some serious head-scratching, I worked it out
I'm not a bastard anymore. Well, as big a bastard anyway.
Back then, in my mid-twenties, I was a heavy-drinking, philandering, ethically-broken moral monster who got bored with being a Belle and Sebastian lyric and decided to try being an Afghan Whigs one for a while. Now... well, I'm less so. I used to describe the joy of being a Spy as playing Thief when everyone else is playing Quake. That's still there - the intricate mind-games which Spies play with their prey, the positioning, the sudden knife in a stupid lunk's back. But the Spy is like the Sniper, but more so - because there's blood on your fingers. You're killing them when they didn't have a chance against you.
(Sniper's are sociopaths to a man, I swear. Parents: Never leave your children with a Sniper as a babysitter. You'll come back to find the kid in question attached to the kitchen wall with a fork through their head.)
The thrill of the Spy is the flip is equally true. If you don't kill them, you're almost certainly going to be reduced to a fashionable red smear on the wall. The gamble's a big buzz, and when it works, you're a fucking genius. Hitting the back of an enemy advance, slicing your dagger through five unwary backs is the sort of thing which makes you want to howl your omnipotence to the skies. That's fun. And how is it different to any other victory in Team Fortress?
The thing is, speaking generally, when you defeat an opponent, their failing is one of skill. When you kill someone as a spy, their failing is one of Trust. Spies predate on people's better natures. They're the kids who'll point that your shoes are undone, then flick it up at your nose. Some would lob balls off a cliff and smirk as the stupid dog runs after it. That's Spy mentality right there.
Spies are evil. But they're a necessary evil. A necessarily awesome evil.
Team Fortress is a team-based game, reliant on close co-operation between a group of individuals for a common goal. Generally speaking, a team who works together towards the common goal will beat a group of individually better players who are playing individually. They may get more kills, but they'll lose. This is heartwarming. This is also a little saccharine. Spies make things more complicated, more interesting. Your relationships with your team-mates are more sophisticated than almost any other multiplayer game, just because your team-mates... well, they may not be your team-mates. They may just be waiting for you to turn your back before sliding a blade into your back. They're Judas to your Christ - the betrayal entirely necessary for the story to be as interesting as it is.
That's my theory, anyway. In some ways, I regret no longer having the temperament for Spy-dom. The Spy's a lot neater in TF2 than in TFC. Why?
Currently, the interesting thing - and the thing which separates good spies from average ones - is an awareness of how invisibility works. There's a fade between visible and not, and knowing what they look like to the opposition at any given moment can be very interesting. I was talking in the pub last night with the best Spy in my social group - mid twenties, ethically broken, argument UPHELD - and considering ways to deliberately feint directions when you've gone invisible. Good players are able to track the invisible foe, and guess where they're going. The ability to mislead that is something that's going to only increase in time, leading to everyone else trying to work out counters.
It's another good example of why the Spy is good for everyone. Not in terms of the frustration of a knife from nowhere ending it all, but in that the mindgames he plays are two-player. Outhinking a spy is one of the most satisfying things in the entire game. And you can gun them down with a clear conscience, because - hey - the little runt started it.
In short, I was lying. I still love spies.
I love killing them. And they love killing me.
Hey - this could be the start of a beautiful friendship.