Things are big in America. That is true of houses, cars and food portions. Perhaps most shocking of all is the size of tips. In much of the rest of the world, gratuities are a small gesture for good service. In American restaurants they are de rigueur. And they are becoming more generous and more common. For workers who already get them, tips are growing; for those who do not get them, tips may be coming their way. But this cannot go on for ever. Look closer at the tipflation gripping America and a surprising conclusion emerges: the country may be approaching peak tip.