Very simple, really.
I don't care who you are, where you're from, or what you do, you can have any opinion you like as long as you follow these simple rules: belittling another for not agreeing with it is flat-out intolerable. Additionally: your opinion is not to contradict a fact; if it does, you negate your right to it. Double additionally: opinions are worth far less if they are not backed up by facts. Examples for the concerned are below!
"I don't like Prototype, I think it's a bad game." "Why's that, Jenkins?" "OMG FUCK YOU QUEER, IT'S THE WORST GAME!"
WRONG!
"I don't like Prototype, I think it's a bad game." "Why's that, Larry?" "Well to me the combat is very boring and I don't think there are enough powers and cool things." "Fair enough; I don't agree, but I'm not a raging lunatic and thus I shall not flame you."
RIGHT!