Heh I saw this topic and had to post!
In my younger days when I was a muppet on gambing machines I used to dread the approach of some twat coming over and telling you how to play the machine. OK fair enough, they may know how to play the machine better than you in some instances but if you really wanted the help that badly you would ask for it.
Anyways, I now work in an arcade part-time while I study at uni and actually ban people who harass holiday makers or people who are minding their own business and are just there to enjoy themselves.
I now play gamblers quite a bit and tend to do OK, if someone makes a suggestion as to how I should play I will take it on board. If they try to tell me how to play they get a swift "f*ck off".
Watch out for "snipers" heheh, I do this myself if someone has clearly left the machine for good and has no intention of coming back to it. Snipers are easy to identify, they seem just as interested in your game as their own. Love it or hate it, its how to make money of gamblers.