Why, when and what?
Problems: You oblige the other to say thanks.
If it is a book, the other might feel obliged to read it (and often you really had in mind to convince the other of something in this indirect way).
If it is an object, you would like know the other uses it.
Money, sometimes, if the person is in need (but only then), is the best solution.
And often it’s the way you do it that counts. And you always risk gaffes.
And after all we are really all misers
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Ever tried. Ever failed. No matter. Try Again. Fail again. Fail better.
--Samuel Beckett