To tip or not to tip

I have deplored the recent growth of "tip jars" at various establishments. I have no problem tipping generously for good service. But I limited my definition of "service" to include only the traditional services one would receive at a sit down restaurant, a bar, or perhaps when getting a haircut. I figured that I had to be sitting and relaxing while someone served me in order to warrant a tip. In other words, why should I tip at the typical coffee joint, for instance, when I have to stand at the counter, find a seat, and then go back up and get my coffee when it is ready. The customer is doing most of the "serving." This being said, I still do tip occasionally at coffee joints etc... when there is good reason to (or maybe it is just that I allow myself to be guilted into it by the tip jar sitting prominently right in front of me).

The reason I bring this up, is that my boss at work has put a tip jar next to the cash register in the shop. The jar is actually a plastic Mt. Bachelor coffee cup on which he has written "Tips - so you don't fall down." I guess that people are supposed to read that and tip me so that I don't purposely mess up their skis or boards thus causing them to fall down. I have greatly appreciated the little extra money the tip jar provides. I can now justify eating out occasionally or spending that few extra dollars here and there. But am I really providing a service that I am not already getting paid for? Am I contributing to a trend I deplore? I probably am, and I should tell myself to "shut up and do your job without whining about tips" just like I always thought about employees at establishments sporting unwarranted tip jars. But for now, I am enjoying the extra cash (let's here it for greed), and in my own little world sticking it to the management of the mountain, who is responsible for my lowly compensation.
Maybe tips should be proportional to the creativity displayed on the tip jar itself.