Personally, I think if it weren't for the crushing discouragement, the joy of publishing your work wouldn't be so amazing. So, call me cruel, but I think it's good to have a little bit of failure in every writer's life. Just a tiny bit, though, to keep you humble. If you've been sending out those clips and working on those drafts and applying for those jobs and god knows what for god knows how long, though, and you're feeling like the man is just keeping you down, well, that's just stinkin' thinkin'. Scott Young has some tips on what you can do to overcome discouragement (I particularly agree with his advice about exercising, although I'd like to amend his advice to make yours an angry workout, so that naturally, while you're burning your calories and thinking of all the things that piss you off, hopefully as your endorphins kick in you'll think of productive ways to make them work for you (I got two or three ideas yesterday from a pissed-off workout last night, thank you very much.)