I like reading plays, but only when I find characters to identify with or when the subject is especially interesting to me. For example, when I read "A Streetcar Named Desire" I absolutely loved it. The characters all had eerily attractive personalities...sort of like you didn't want to like them, but a part of you did.
I think you are completely right on this point! I am a fairly slow reader, and I think that this helps me to understand the plot better and imagine the script in my mind as if it were on stage...i.e. the rooms all being visible from my perspective, the animated acting, etc. It gets pretty fun!