A relationship is pointless when THIS happens
I don't care how much a person likes someone else. If you have to fake your personality to impress them, it's not worth it.
On the other hand, you know when you're with the right person when you feel comfortable enough letting your true colors come out.
Sure, in the beginning of the relationship, people try extra hard to make a good impression, doing their best to hide all their flaws. But sooner or later, a genuine version of yourself should be in evidence.
You shouldn't have to force yourself to like or support something only because the other person does.
Part of being in a relationship involves accepting each others' differences. Just because your partner is a football fanatic or history buff doesn't mean you to have to be one.
Having different views and disparate hobbies can be advantageous to a relationship. The former can make for interesting discussions and debates among the two of you, while the latter can allow you to partake in each other's interests. In many cases, both people end up adopting each other's views and taking up some of the other's hobbies.
However, if having dissimilar views and interests leads to too much friction in a relationship -- that kind that's beyond compromise -- it's better to end it and find someone who suits both people better.
No matter how wonderful someone may seem, they should never prompt you to change who you are. Impressing the individual at the cost of putting up a facade and not being true to yourself is an exercise in futility. Without a doubt, that's a relationship destined for failure.
Be yourself -- and be proud of it! Don't settle for someone who wants a phony version for you. Wait for the person who will love and appreciate you just as you are.