This is really the only thing I think is just a bad thing to do. If you enjoy something or don't, it's up to you. Unless you're writing a review, you don't really have to explain why you do or don't like something. If if you do like it, I'd say at least give it a like. Not liking it because it has 30+ likes. No offence but that just sounds petty. Also every like counts and motivates the writer.