Quote by Mark Twain, Autobiography
...gratitude is a debt which usually goes on accumulating like blackmail; the more you pay, the more is exacted. In time, you are made to realize that the kindness done you is become a curse and you wish it had not happened.

Summary
This quote suggests that gratitude can be seen as a never-ending obligation. When someone does something kind for you and you express thanks, it creates a sense of indebtedness. Over time, this debt of gratitude can continue to grow, similar to a blackmail payment. Eventually, the act of kindness can become burdensome and unwanted, leading to regrets and a desire for it to never have occurred. This quote highlights the complex nature of gratitude and the potential negative consequences that can arise from a continuous cycle of indebtedness.