concurs with the majority of posters here. the key is having good technique and knowing when to back off if missed. all problems arise from large amounts of missed liquid or abscess in swim's estimation. swim must admit though that the hands have been an invaluable place for spotting veins and hitting easily and with the least pain.
swim, believe it or not, feels that most pricks in the hand are less painful than forearm shots, though obviously biceps are best. however, exceptions are the topsides of the fingers, especially in the thumbs for swim; the other digits seem to take topside injection ok so long as swim stays at a virtually flat 10-30 degree angle arc, unless swim hits bone of course... YOUCH! (mostly what the 10-30 degree arc prevents, btw). and major pains can be had on the underside of the hand due to the type of sensitive skin; swim emphatically stresses the use of a fresh out of the package needle tips on the underside of the hand (he prefers 27g, never longer than .5" -- its large enough to move more liquid quicker, but not so large its a pain).
hope this helps any of you