Getting bloodwork

Since I'm getting older, I have been required to get blood tests once or twice a year.  I went in to Spectrum Health in Sparta a couple of days ago, and the nice young lady asked if I had a preference for which arm she would attack.  I said "Of course I have a preference","I'm 66 years old."  "Which arm?" she asked.  "Well, I have a preference, but I can't remember what it is."