How can you troll a thumbs up system?

Say what you will about how Facebook does business, this isn't about that. It's impossible to troll a liking system, you either give the story a thumbs up or you don't. What are the trolls going to do? Like something that they actually didn't and give you a false feeling of self esteem? It's not like the number system is there for constructive feedback anyway, we just want to know that people are reading our stuff and enjoying it. Therefore only giving people a positive option in that regard will take care of the trolling problem.