There Are No More Good Things

Asimov once wrote[0] that it's possible to try to write suspense, miss and be slightly suspenseful, you can try to write horror, miss, and be slightly horrific. But try to write humor and miss, and what you get is of no value at all.

[0] This is badly reconstruct from memory - I'll try to find the reference[1] ...

[1] This isn't the exact reference I had in mind, but it's close:

"There is no way of being almost funny or mildly funny or fairly funny or tolerably funny. You are either funny or not funny and there is nothing in between. And usually it is the writer who thinks he is funny and the reader who thinks he isn't."

-- Buy Jupiter and Other Stories (1975), p. 33 (in my copy).