By the strange measures of late-night television, the moment was quiet and maybe even forgettable. Except that the look on Fallon’s face solidified for me what I’ve always felt about him, a man I have not met and do not know: I believe he has earned everything he has received, because not long after he was born he began to study the men who came before him, and he practiced and he learned and he practiced some more. Before Jimmy Fallon talked for a living, he listened.