Although my trips to the beauty salon are just for haircuts every few months (and I have been going to the same lady for the past few years), I too don't see the need for an extra gift at Xmas. Maybe I am somewhat of a scrouge, but I do think some people get carried away on this tipping and gifting at Christmas. You pay for the service when you go, and you tip each time you go, and if you really like the job this person does, then you tip well each time. This is their job, and this is what they get paid for when they do it. And I do understand that "tipping" is expected because their base pay is usually very minimal.
As far as the mailman (or more correctly, the letter carrier), I truly don't understand why so many people give them tips. They're doing their job. And actually I think they get very well paid, and have outstanding benefits, so why should I tip them for doing their job?
Someone I tip during the year is the garbageman. I do this when we have a larger than average pickup--like if we clean out the garage and have a lot of stuff. But I watch for him, and give him some extra bucks when he comes.
These are guys I think that are really underappreciated.