Jimmy Fallon's Top 10 reasons why David Letterman's retiring: Watch

jimmy-fallon-david-letterman-retiring-because.jpg After Jimmy Fallon heard the news of his fellow late-night host David Letterman's retirement, he decided to pay tribute to his mentor by dedicating a Top 10 list to him ... for reasons why he's retiring. 

"It's hard to imagine late night without him because he revolutionized it and made it what it is today," Fallon says seriously, before launching into his list. Some reasons were downright hilarious, some were a dud (seriously, not a single laugh to be heard for one of them), but the top reason is just the best.

Watch Fallon's list below:

Photo/Video credit: NBC