This question was brought to you by Medics’s siblings. I finally did this for you, now shut up.
Aabicus: Snipers can be teeth-gnashingly annoying, but in all honesty they don’t bug me as much as they could. I’ve since learned to be very careful before crossing into territory where a sniper could see me, and unlike most classes, I’ve got a way to turn myself invincible against all damage, for when I finally poke my head out. That’s not to say that sniper’s niche of “deals lethal damage from the other side of the map” isn’t incredibly difficult to counter as anything but another Sniper, but most of the good maps have ways to limit good sniper lines. Also, we’re not playing Team Fortress Classic.
For those who don’t know, the TFC Sniper Rifle could charge/headshot from the hip, charge-up damage infinitely (so you could OHKO lvl 3 sentries if you charged long enough), slow enemies on bodyshot, and had an alt-mode which turned it into a perfect-accuracy rapidfire machine gun that shredded anyone in seconds. It’s only “downside” was eating through your ammo reserve. So, as long as I’m not playing against that, I can count my lucky stars.
Medic: With a name like this, why do you think? Snipers are always gunning for me. That’s their job. But I’m okay with Snipers gunning for me really, because as I said, I know it’s their job. No, what annoys me the most about Snipers is that really, they are safe no matter where you get them from. Most Snipers are found behind their team, shooting from a distance, at places where only Spies and lost Pyros travel. But they’re also safe because of all their damned unlocks. They’re safe from other Snipers with the Danger Shield. They stop flinching with the Cozy Camper. The Razorback forces Spies to not do that one damned thing that they’re designed to do – instantly kill with a backstab. Few classes get this ability to protect themselves from their main threats without sacrificing their efficiency.
Oh, don’t get me wrong, I hate other classes too. But I also love them as they’ll generally give me a hand, even in the worst situations. Snipers though will just hide away, playing their point and click adventure, using me as target practice.
iGamr: The obvious answer is that they’re a long-range hitscan instakill class in a game mostly centered around short-to-mid-range combat. It’s rather obvious why that would be irritating; after all, nobody wants to be in the middle of a firefight only to drop dead because somebody a mile away from the action had a line of sight, which is made even more aggravating by the fact that, by its very nature, the only sure counter to a Sniper is yet another Sniper. Sure, Spies can get instant kills via their backstabs, but they have to navigate around the enemy team and get within melee distance of their target to do so, making that kill much more “earned” than “given”.
My two larger complaints, however, are ones discussed much less often. The Sniper has a virtually infinite skill ceiling and, as such, is deadly at any range imaginable. If the Sniper were designed in such a way that dealing significant headshot damage required him to be far enough from his target, I would find his existence in TF2 much more forgivable. He would be filling his specific role much in the way that the other classes do, and the previously mentioned short-to-mid-range combat would be a weakness enforced by the game mechanics. However, since his weapon’s damage is constant regardless of range, this weakness is only theoretical. A Sniper with enough skill can, at any distance, effectively deal at least 150 damage at a moment’s notice via a well-placed headshot, which only takes a fifth of a second. If one has managed to get within close proximity of a Sniper, they have earned their advantage, and getting that far only to be taken down without a reasonable amount of time to react is simply not fair. While other classes must use a myriad of skills to gain the upper hand in combat, the Sniper relies almost solely on aim, and that makes dealing with him completely intolerable.