I ended up playing Katawa Shoujo after a friend of mine talked about it to me one day. Spent about the next year hovering round those forums like a bad smell, while playing any free VNs I could find. I loved (and still love) the feelings that I develop towards characters while reading, be it because of their design (it normally is), voice, backstory, quirks and what-have-you. A good VN is one that I'm thinking about for what feels like forever after I read it.
The main barrier for me - well, there's two - is that I don't like pirating shit. It scares me, to be honest, and while I'm hardly flush with money I like paying for things where I can.
The second is the content. I am the vanilla-est, most easily bothered reader of these things that you'll come across. As such, I won't play most VNs, cos either I can't afford them, or I don't like what's in them. And that's fine, cos there's still plenty of highly-rated, very safe-for-lifework ones for me to read