@Mor - Well, it's worse when you can't find your own vein I guess. I have a friend who is diabetic and one of the things that people don't realize is that eventually they start to run out of places to stick the needles.
The usual areas just become too traumatized, with collapsed veins and scarring and they run the risk of infection or worse, so they keep having to find new places to inject their medication.
I think that there are some new methods of delivering insulin now so that this isn't as much of a problem. I imagine one day we won't have to worry about collapsed veins or anything similar because they'll be able to administer everything without breaking the skin.