"that show is horrible!"
*speaks in slightly higher pitch and to the side* "I don't know, that show seems pretty good. Why not give it a try?"
*speaks normally* "I agree random stranger!"
Try to disprove their comments if possible and then state why you like the show. If you do it in that order, then they'll think you're a douche and never talk to you again. So, mix it up a bit.
*hides every piece of FMA merch in backpack*
*speaks in slightly higher pitch and to the side* "I don't know, that show seems pretty good. Why not give it a try?"
*speaks normally* "I agree random stranger!"