I remembered on a business trip, there was six of us and that was just enough to kick in the gratuity charge. When we walked into the restaurant, the lady who served us mentioned that mandatory 15% gratuity and she was kind of nasty about it. My boss remarked that it must be the max limit and she walked away. We got crappy service the whole time. Also, one of the company executives was with us as well. After the meal, it was decided that we will not patronize the establishment again. I would object to the charge if the service was crappy but I can also see the charge so the servers don't get stiffed either.
I waited tables and tended bar for quite some time. The establishment I worked in added an 18% service charge/gratuity (whatever you want to call it) for parties of 8 or more. My attitude about these parties was to give them extra special service, although I always did my best to give all of my guests great service...granted there are times when things out of your own control make the diners' experience less than what you wish for it to be (and there are also persons in the world who just should NEVER go out to a restaurant as they are never satisfied with anything...and then there are the persons who go out, eat and drink a lot, say everything is great until the bill arrives! Then suddenly things weren't so great after all and they start complaining to the manager. My old manager was very good with these people but he always knew when they were just looking for a comp! ...but one could write a book on all of that!)
Anyway...as I was saying, I always tried to be extra attentive to the larger parties as I considered the fact that if this large group had a positive experience and were happy with their service, they would return, and in turn recommend the restaurant to others. It's just good business to give extra-special service to the parties that are large enough to have the service charge added. Most of the time I ended up getting an extra 5 - 10 % on top of the service charge and when these groups returned, they'd request that I be their server. So it was very beneficial to me money-wise.
And it is true, waiting tables is NOT easy...at least not in a higher-end, busy restaurant. It's the job a a good server to make it look easy though. The best ones always make it seem simple...