When it comes to having blood drawn, there is no advantage to having a fine needle used.[snip]Let the lab lady decide.

The advantage of a small needle is immediately apparent to belonephobes[1] like myself. With a sufficiently small needle and a sufficiently skilled phlebotomist[2], the process of drawing blood can be almost painless. I have always been inexplicably terrified of any sort of hypodermic needle, but the last time I had blood drawn I literally felt nothing as the very skilled "lab lady" pierced the skin and got a vein on the first try, while the nurse at my doctor's office tried three times in each arm before giving up and sending me to the hospital to have it done there.

[1] Those with a fear of needles
[2] Someone who draws/analyzes blood -- phlebotomist is a great word, but I do like "lab lady." It's much friendlier, unless of course your phlebotomist is a "lab gent."