I also have no climbing glee - my achilles tendon's a bit ouchie, so I decided I should rest it :-/

I've used auto-belayers at one wall (in Kinlochleven), and they do give me the Fear a bit. I think the real danger is not having someone to check your knot; it's hard to rest on them, because if you just lean gently on the rope, it lowers you slowly - you have jump/fall a bit to make the stop kick in.