We talk tip all the time, but it made me think, "What industries get tips and why?"

We tip people who cut our hair, but not mechanics.  

If a mechanic does a great job on our car, we are thankful. May even 'repeat' or tell others. If we keep coming back, the garage is thankful and appreciative. Is it because we don't know what kind of job he did on our car, so its not an immediate thank you? We certainly don't drive back the next day and say, hey my car is running great, here is 20% on the entire bill. One could argue if you did tip, it would be 20% on the labor. But that doesn't make sense either. You don't parse the wine and steak from the service minimum of $2.85 an hour.

Is it work on an inanimate object, your car? But we tip valets for bringing us our car.  

If you tip the valet a couple bucks for bringing back your car, that is WAY more than 20% for his work. Tip the doorman for bringing in your suitcases, again a few bucks is a lot more than 20% for a miniscule amount of work.

We don't tip at Chick Filet, and they'll refill your soda for you without you having to get up, 5% tip?
No tip for grocery bagger. Why not tip them 10% of the total bill for bagging your groceries? Makes more sense than the standard 20% tip for all restaurants. Does the server at Morton's do more work than the server at Fridays?

No tip for mailman, no tip for Doctors, no tip for providers - and no, the tip of your dick doesn't count.  

Does anybody NOT tip at restaurants. I mean NO tip at all? If you're not going back, why even tip? Social pressure? They aren't going to spit in your food, you already have eaten. I tip 20% on the total bill. I have friends who do it pre-tax. Maybe I should just carry mini canoes with me.  Who knows.

Tipping is just weird.

It was not a part of the culture in Australia back then.  Pay for service industry workers was much higher than here. It was the employers responsibility to pay it's staff a fair wage for their work. Tipping   is much more common, in fact expected now, after the last 30 years of American tourists getting people used to it.

It clearly grew here in service  industries that didn't pay it's employees shit for wages. So many servers etc. not making enough to live on so tipping was a way to get pre tax money to the workers. And employers don't have to pay post tax money to them.
It is a carrot dangled to bring out better service from the almost slave labor.  
So, that's probably why some employees don't get tipped. They get paid, or the perception is that they get paid and you have been trained to think that way.

...and too deep for me this early in the morning. Now where is my tequila?

To answer your question about Chick Fil A and grocery baggers, those people are paid minimum wage or higher whereas servers are paid under minimum wage. That's why they get tips.

I tip 20% on the total bill but I'd rather just have prices increased so that the server can make minimum wage instead of having to tip

by tipping only for services I deem to be of a "personal" nature.  Examples would be barber, manicurist, valets, shoe shines, hotel staff, and of course, a woman providing me with a warm place to park my dick for an hour or two.  I would also tip a plumber who came to my house on a Sunday morning to unclog a toilet plugged up by an outcall provider who spent the night.  However, most mechanical or repair-type services do not rise to my definition of a "personal" service under normal circumstances.  

END OF MESSAGE

What you do for a living seems to have a big impact as well. I think everyone will agree that bartenders are among the best tippers for example.

 
Speaking for myself, I spent my late teens-early twenties living in Las Vegas where it seems that everyone lives on tips, consequently I am a pretty big tipper. I'll often leave a twenty for a five dollar beer, but OTOH I can be a total prick, getting back to what the OP said, I am the kind of guy who can leave one thin dime on a hundred dollar check if I think the waitstaff was rude or lazy and I will do so just to make the point that their service was unacceptable. I do NOT subscribe to the policy of giving EVERYONE 20%. On average I am a huge overtipper, but I don't get embarrassed for undertipping or down right "stiffing" for substandard service.

 
Where it comes to hookers, I am really not that big a tipper, and I am more prone to tip the lower priced girls than the women with GPS, a girl only charging $250 (not that uncommon in Texas) will almost certainly get rounded up to $300 if she provides me even halfway decent service, but once a provider gets into the $400+ range I treat her like any other professional service provider and assume she has set the price she believes she deserves, and my "tip" will be return visits.

I tip primarily on the quality of service of those that I believe are making below a certain threshold.  If I'm using a service that generally pays minimum wage or less and the service is good, I'll tip a certain amount.  I find it silly to tip based on the bill.  Why should someone get 20% off a large pepsi but someone gets less if it's a small pepsi?  It's the same amount of work.  Why should the lady that cuts my hair only get $3 for spending a solid 15 minutes with me, yet a waitress spends maybe 5 minutes with me can get a much larger tip?

Then there's the quality of service.  I'm sorry to those that survive off tips that may get offended at this, but just because you take my order and bring my plate does not mean you get a tip more than a few bucks (if that even).  If my drink remains empty without you asking about it, if you don't ask how my meal was, if you act like you deserve a tip just for being there, then no...I'd be more likely to hand the tip to the chef than give it directly to my wait staff for poor service.

But when someone charges $100s per hour, I see no need for a tip.  My tip would be repeat service or I'd recommend your service to someone.  I will tip for an emergency or if someone goes beyond the call of duty to do something for me.

I'm a needy monger and I think the ladies that are in the $250 range are going above and beyond their pay scale with me. I too increase the compensation appropriately.
I don't look at it as a tip. I look at it as being a good client and friend.

Tipped an agency girl 200 on a 300/hr visit. I was new to it, and she tugged on my heart strings. Telling me how slow it was and she wasn't doing well. Then every subsequent visit had a sob story. I may drop between 20-50 extra on an exceptional provider, but I'm a frequent flyer, so my budget is my 1st priority.

so do I.

LLAP,
Swim