Saying thanks when you do not mean it is as frivolous as saying thanks when you do not mean it. Well, I guess there is nothing comparable to that - more or less, good or bad possible but nothing comparable.
We all take troubles for the ones we care for and we love, mostly without expecting anything in return. But what would you do when your child turns back and says - thanks for your trouble man! I mean, what would one do but smile and hug the child one more time. And what would one do if one comes to realize that the thanks was an emotional moment, or worse, unmeant?? Well, I guess one would smile and ... well, just smile - for there is no child to hug anymore!!
Life would have been so-so much better without words... better to say nothing than ... !!!