What I hate is when someone gets uber-excited about x and I don't, they then get offended because they think I don't like it all that much or that I don't like

What I hate is when someone gets uber-excited about x and I don't, they then get offended because they think I don't like it all that much or that I don't like them. Yet if I say something critical (constructive or not) about x, they also get offended, even if they have nothing to do with it. I guess there's no 'right' thing to say.