As much as I love Jimmy Fallon (and I really do), the guy is so generous and full of unmasked adoration that it’s pretty easy for guests to overshadow him on his own show. Case in point: being in the same room as Bill Cosby. Jimmy may try to keep up with what he initially sees as some equal-sided improv exercise, but it’s immediately apparent that that’s not what this is. This is a time for Jimmy to sit quietly and take notes. Anything more really does make him look like the cloying third grader Cosby teases him to be.