I can definately relate. I find myself sizing up peoples veins all the time. My nephew was over this past weekend and he had a huge vein in his wrist, I immediately starting palpating it and describing how easy a stick he'd be!
When I worked in the ER and had crazy shifts I used to do things in my sleep like take my husbands pulse or feel for a vein. He would tell me that if I started sleep walking and came at him with something sharp he wouldn't be responsible for what he might do to me, LOL
nj