Interesting responses. I had a severe elbow injury from biking that had me out for quite a while. Once I got back on the bike, I was somewhat surprised that I really had no instinctual fear that had set in from the injury. I've been mtbing for 10 years or so, and I think the familiarity of the activity overrides the memory of the split second mistake that caused the injury.
In general though, fear is a good, healthy emotion, despite what the Nike ads may tell you. If you have a fear of riding something, it may be a sign that you don't have the skills for it, so I'd listen to it carefully. As for myself, even though I don't get butterflies in my stomach looking at something, intellectually I've had to severely adjust my risk tolerance. I know if I have another injury to my elbow the long term consequences could be quite severe, so I simply won't ride some things I used to because the risk of re-injury is too great. I.e. the fun to risk ratio is not so good because the risk has gotten higher.
So I wouldn't worry about it, but if you do find yourself feeling more fearful, maybe it's thousands of years of evolution kicking in telling you not to break your wrist again. I say don't fight Darwin, practice on some safer terrain and slowly build up or back up to where you want to be.