I've had several birds get under my skin that I never did kill but I've never knowingly hunted a bird more than one season. Even on private land I've not found a bird that was consistent enough from one year to the next to confidently say I'm hunting the same bird. Also, I've eventually killed several that had gotten under my skin that I was convinced would be old hooked spurred toms that turned out to be nothing special other than a tom just being a tom.
I have no problem pulling the trigger on a bird I've hunted hard enough to feel like I know him. There is always another bird to take his place.