I think most folks here know of my antipathy for the traditional publishing world. That said, I get the excitement that comes with someone in some official position saying your work is good enough to publish at their company. I once shared that goal, and I'd be less than honest if I didn't say that some movie producer coming to me wouldn't get me all hot-and-bothered.
Unfortunately, some first-time authors are so desperate to get that first contract that they'll waive their rights without reading through the contract offered. They'll grant the publishing company rights and carve-outs they're not entitled to. After all, with the consolidation of the traditional publishing world into fewer and fewer companies, many feel that if they demand fairness, they'll never get a contract offered again.
First of all, you need to have enough pride to accept that it's true you may never get offered another contract. And you should be okay with that. If someone wants to take advantage of you, you come off like that fat friend who never got a date and is willing to be treated like shit just to say you have a date. No one respects a kiss-ass, and you'll get treated like dirt your entire career.
Second, publishing is still a business, and if your work is good enough, another publisher will offer you a chance. You may not get JK Rowling money until you prove yourself, but money and sales have a way of softening hard hearts in the publishing world.
If you sell yourself out just to get published, you'll be a doormat forever, for even when you realize your worth, no one will grant you that respect because you licked their boots prior. You need to know when to insist on either inserting or removing some contract items, and when to walk away because they won't remove your red lines. You'll be better off as a person, rather than a sellout, in the end. After all, it's you who has to look yourself in the mirror each morning.