I think victory feeling good should be an incentive to PvP, and that defeat should not necessarily make a person feel bad in most forms of PvP. Not all, but most.
For example, if I'm an arena fighter in a contest on fair terms, winning and losing should both feel good. The fight should be thrilling, challenging, and educational no matter the outcome. On the other hand, if I'm robbed and killed on the highway, or by someone I trust, I can't see many situations in which I would feel good about it, or want to for that matter. However, the satisfaction of revenge should be enough to motivate me to seek it out, rather than giving up and trying to shrug it off or stop playing instead.
But to look to the core of the counter-argument against all PvP feeling good: Unfair ground is a big part of the thrill for PvP players. There's a lot of people who love to win, but hate to lose. These are the players you'll find ambushing gatherers and levellers in other MMOs, or running in packs/zergs and devouring everything they encounter. Most of the really interesting PvP experiences in gaming happen in the grey areas where unfair PvP is possible, as situations develop and unfold in a chaotic manner. Ambushes can turn into routs, hunters can become the hunted. The prey can walk away as the last person standing. The factions in one encounter - or string of encounters - can number a dozen or more. These encounters, too, have the potential to be thrilling, challenging, and educational. Not as easily, true. But the encounters that are are that much more interesting for the unpredictability of it all.
Which is why those of us who want PvP are so vehemently against any kind of flagging, battle instancing, or other restrictions on open world PvP. There's a whole other game in the wild that we can't experience if things are too tightly constrained by rules and safety nets. Hell, a good number of us will protect those of you who don't want to fall prey to this sort of activity just so we can put ourselves in harm's way so it can happen. Remember that much of the game's dynamic is going to be built around co-operation and mutual benefit. Around contracts. Small jobs like escorting people between towns or scouting someone's land to clear it of bandits are going to be big draws to PvP players, simply for the chance that there might be other players involved. Your needs as a noncombatant are going to be met. You'll just need to work for it, as we will need to work to meet ours.