When I was a book seller (for years and years) I was called upon to give my opinion about books on a daily basis. Now, this can be tricky. If I tell someone about a book that I hated, that I think sucked, and I say it's the greatest thing ever, then that's a lie. And if they buy that book based on my lie, and hate the book, then guess what? I've lost all of my credibility.
Over the years, I learned the value of tact. It's perfectly okay to say to someone asking about, say, Henry Miller, that "I'm not the best person to ask for a recommendation. I don't personally care for him. I think he's a little too gimmicky." If they asked for more, I'd tell them what made Miller's writing more of a blog trick than actual prose. But I'd always end with, "But that's just me. Other folks here love Miller and can tell you why he's great." I'm not putting down anyone who likes Miller. I'm just explaining why I don't. See how that works? Let me say this out loud, so there can be no misunderstanding: if you're not capable of doing that every time you hit a movie, or book, or record that you don't like, then you're not going to be an effective critic. You're just going to be another nameless, faceless voice in an already crowded Internet yelling "IT SUCKS" from the other side of the lake.
Take a moment to decide if you're a reviewer, or if you're just a reader. If you want to be a reviewer, then you've got to be brilliant. Or gifted. Or both. But if you just want to be a reader, and just want to be able to say what you think, without all of that other stuff getting in the way, then make the effort to say what you mean and mean what you say. Use your words. You're a reader. You of all people should know the value of written communication.
An issue I'd been wrestling with a bit: am I a reader, or a critic? I've done a bit of both: I've offered my opinions on things without necessarily critiquing them, and I've also done breakdowns and analyses. But which of the two am I aiming for? In fact, why choose?
