Just understanding how negotiations work removes the frustration.
I read a book about negotiating. It had the usual breakdown of strategies, tactics and scenarios, and a lot of filler, but it was entertaining to read. Today I'm still not a good negotiator. Normally I just don't want to waste my time and just want to get something, or I don't want to "squeeze" the other side for little profit.
But I know that on big key deals, like buying a house, a car, or getting a job, there it is well worth to apply some pressure. And if I don't get to my goal, or if a deal fails, now I understand why and don't feel so much frustration as before.
> or I don't want to "squeeze" the other side for little profit.
That's exactly how I feel! That's why I believe it is important to understand the process. When you negotiate with a company, you're not squeezing the other side for profit. They just won't accept anything unreasonable. But in case they want to squeeze you (which is likely), then you should defend yourself.
I've found that it's a good idea to practice such skills when buying things in $100 and above range, especially if you are directly talking to the seller. It almost never hurts to ask "hey, I see the price is X, I like your product, would you be able to squeeze in some discount?" with a smile on your face. Even if for a 2% discount.