I've never been a big fan of improvisation, because I think you appreciate the process and the cleverness of it more than the actual comedy in most cases.
I'm not able to go in with an act that I use month to month year to year all the time. It's constantly evolving and changing and that keeps me on my toes but certainly adds to the challenge.
I've always felt that improv looks and feels more clever when you're there to experience it live than when you have the degree of separation that television creates. Television raises expectations.