Scientific progress is built on testing hypotheses and refining our ideas about the world. We test and re-test hypotheses until we are satisfied that they are supported (or not). An inner belief or intuition is not enough to convince any scientist that a particular hypothesis is true. In other words, the words "I believe in evolution" are meaningless. It's the bountiful evidence for evolution that has convinced every biologist that it is a fact. The greatest thing about the majority of scientists is also that they're willing to discard even their most beloved hypotheses in the wake of new evidence.
However, I think it is sometimes easy to get involved in personal rivalry over competing hypotheses. I have seen people at conferences very nearly yelling at each other and even heard stories about death threats! This is not appropriate conduct for anyone, let alone an educated scientist. In my opinion, you should never take a disagreement with your hypothesis (no matter how awesome!) personally. It's not an insult. It is on disagreement that scientific progress is built! Every time a reviewer or fellow conference attendee disagrees with me, I take time to remind myself that they are enabling science to move forward. After all, if each of us stuck with our respective hypotheses and worked only to find support for them, we would not know that the earth revolves around the sun or that the big bang really happened!
But how should we disagree with each other in a productive way? If someone disagrees with you, it is their responsibility to demonstrate convincingly that your hypothesis is not supported and not to call you names (the reverse is also true). Probably the best outlet for debate is in the scientific literature. Firstly, publication avoids name calling and death threats (usually!). It is important to avoid personal slurs in print. This does not reflect on the person you are refuting, only on you. It doesn't do anyone any good to gain a reputation as a whiner. But if you are scientific and careful in presenting your evidence, you will gain a reputation as a respectable scientist. Secondly, publication involves other scientists in the debate. Broadening your audience will always bring unexpected insight.
Most importantly, if it is demonstrated that your beloved hypothesis is not supported, you should discard it. There is no merit in clinging to debunked ideas. Of course, I think the VAST majority of us scientists find new hypotheses exhilarating and are therefore unlikely to marry any particular one. That's what I love about science!!!