Supernatural is one of those shows that I'd always meant to watch. But, as I have so many films to watch I tend to put them first, plus I don't really watch much TV, and rarely know what's on and when.
So... I've never seen it and it joins a list of other shows I'd meant to watch but never have done. I've never seen an episode of 24, Lost, or Heroes and I've always meant to start watching them online or series linking them on Sky, but I never seem to remember.
I don't really like blind-buying TV boxsets either, just in case I don't like them - plus some are pretty expensive.