Here's a common human trick: before you state your complaint, wind yourself up with a preface that makes your complaint even more plaintive and more vivid.
"Do you know who I am!"
"I saved up for four years for this vacation and paid your top of the line rate..."
"I've told you a million times that the most important feature was this, and in fact the only reason I bought your product was..."
"I've worked my butt off for him for years, showing up even on holidays, and now..."
You've heard it, and perhaps you've done it.
It's interesting to trick yourself by doing precisely the opposite.
"In this economy, I'm lucky to have this job, and it's almost perfect. It would be even better if..."
"I love owning this device, it lets me manage my life and contacts, and the one thing that would make it even better is..."
It's important to leave out the word "but."
The fascinating thing about this approach is that not only does it make you happier when you say it, it increases the chance that the person you're complaining to will actually do something to help you.