Well at the risk of getting slammed - let me first say I have been a chef, bartender and waiter. I do not tip everybody and their dog. Barbers, paper delivery, mailman, ect. I am paying a fee for the service they provide. When I pay my newspaper subscripton it is for home delivery. I feel I am paying to have it delivered. I do not feel I need to subsidize the wealthy newspapers business by paying the delivery guy (girl). If they need to pay them more raise my rates. I apply this to most situations. Now when it comes to personal service that's a whole different ballgame. A realy attentive, friendly waitperson,, bartender, masseur or any other personal contact person I tip based on service.
We purchased a custom pool table several years ago and paid a fair amount for it including the table being delivered and assembled. The installers were ok, but when they opened their toolbox they had a huge red sign that said "Tips welcome". I asked them (when they were finished of course) if they had done anything special or unique to my table and one of them replied "naw they're all pretty much the same". Now what would I have been tipping for?
Before you start typing, I am known to overtip often. So much so it makes others in the group mad, becaue they look bad. Tipping is suppossed to be a reflection of gratitude so if you feel your barber did an exceptional job by all means tip them. If your paper delivery person treats you above what your paying for, tip them.
As for tour guides, parasail employees, dive operators, etc. I am also paying a fee for a service. When I am treated especially well and have had a blast, I tip. I have been on dives where the crew did little, pointed out nothing in the water, and were quite frankly very curt. No tip.
I have my regular hangouts and I get great service becasue the staff have gotten to know me and know I will tip for great service. We do travel alot to foreign countries and we attempt to learn the customs before going. i.e. In the tropics, slow down, do not rush anything, it is more laid back than downtown Dallas. In Italy, meals are to be treated as an experience, thus slow.
So don't worry about getting tipped whilest I am there as long as you are friendly and provide good service. I don't expect to be waited on hand and foot and I'll drink my Belikin's from the bottle so no one has to wash up for me.
Now start typing.