What do you feel about players that do perpetual checks when they are losing?

If you think it's cheap, you're probably smoking that MaryJuana, MaryandJuana.

     There is no such thing as "winning by material advantage". Either you can checkmate your opponent or you can't. Going after material and neglecting your own king's safety often leads to disaster--just look at how many of Morphy's games ended with him down decisive material because he sacrificed most of his pieces in mating combinations.

     No matter how strong your attacking position, it is irrelevant should you leave your own king exposed to a counterattack, even if that attack is only sufficient to get a perpetual check.

A:  If I'm behind and I can put a king in check and keep putting him in check then I have the initiative and opponent can't deliver a coup d'grace.  And as long as I have the initiative, there's always the chance my opponent can hang a piece.  I've seen opponents hang rooks and queens getting harassed like this.  I myself turned a game around the other day down two pieces by gaining the initiative and just harassing their king waiting for them to make a mistake by hanging a piece, or allowing a fork or a skewer.   

Doesn't aways work.  But works enough to make it worthwhile.

If they have a perpetual check then they're not in a losing position, they're in a drawn one

They're mass-producing them these days.

When you checkmate somebody, you are only able to win because of the rules of the game.

It's like asking "how do you feel about blundering a completely winning endgame and making a draw?..." Uh... I feel... Traumatized by it?... lol

They call it "Blundering a perpetual" for a reason... But hey be easy on yourself it even happens to GMs once in a blue moon....

its part of the game tactics

I checked someone about 30 times in a row to wind down his clock and until he blundered just the other day. I offered a draw after the 5th check but he refused, so I keep checking, I eventually won the game on time

In blitz .. continual nuisance checks [as opposed to perpetual check ]

in a losing position are annoying and puerile.

Just because someone can't escape checks (though he can escape a threefold repetition) doesn't mean that isn't a valid path to pursue.

recently i thought for sure i had the win. then my opponent drew me with perpetual check. i felt just as you described, if not worse for missing it.

'What do you feel about players...'
I have no feelings related to them, LOL. It's fair and, if you have an opportunity to save your life and stay alive, you must use it regardless of the opponent's feelings.

They're pathetic...

Excerpt from a game:

It's nothing but delaying the inevitable, what purpose does it serve?
After losing the queen they finally played the logical moves and resigned a few moves later, which they should've done before the pointless checks, since there was no way to avoid losing. Worst part of it all was that they actually took about half a minute to think about those checks. 
If you take your time and come up with a genius move: all the better for you. But when you clearly know you've lost (otherwise they wouldn't be going to the perpetual check), stop wasting time: just make a move (even if it's a useless check) or resign.

Honestly, the only time you should be perpetually checking is if it serves the purpose of getting the king where you need him to be to either win the game or win a piece.

But apparently the game of chess has some weird psychological impact on some people where they just can't accept a loss and resort to infantile behaviour.

Edit: Here's an example of when you do need to perpetually check after move 40 (because of a mistake I made, but still winning, so not checking out of spite, but to secure the win, and otherwise it would've simply been constant checks until checkmate anyway)

Maybe, and this is just a suggestion to those who hate being perpetually checked when you're "winning", you could try NOT putting yourself in a position where you can be perpetually checked?

you need to shift your perspective. If your opponent allows a position where you the losing side can land perpetual check, he wasnt winning to begin with. ( he was only winning prior to allowing that possibility to happen).

Just like stalemate is a fact of life in chess, so is the threat of perpetual check. You have to learn to take advantage of it when it is in your favor

Regardless of points on the board, you're never winning when your King can be chased endlessly. Perpetual check is somewhere between checkmate and safety. A draw is the appropriate result. 

As it turns out, the OP has several draws by perpetual since then - and in one instance in 2015, the OP, who was on the materially disadvantaged side, had to give checks repeatedly using the queen to save the draw.

Giving perpetual checks is what you are supposed to do if you are losing.