The ending ah come on!?

I was enjoying the forboding atmosphere build up but that non-descript ending was a bit of a let down for me!? Did I miss something and need to watch the last bit again? SPOILER ALERT... Loved how the hitcher got more and more of a menacing vibe to him as it went along. I thought he was going to turn out to be the devil or the grim reaper or a victim of the drivers crime but i don't know what his link was. Anyone else watch this?