Under the skin was one of those films that upon first viewing I didn't really like, but the second time I found it great. I think the first time I was just in the wrong mindset and not managing to fully submerge into the film's atmosphere.

I watched it once more after reading the novel it is based on (I really got into Michel Faber's writing after reading Crimson Petal and The Book of Strange New Things) and I was really fascinated by its eerie and otherworldly feel; also learning how it was filmed (using hidden cameras to record real people's reactions) helped me appreciate it more.

I might include it here in the future, @drummond Thanks for the idea!