Well, you probably already know, but there may be other reasons you haven´t considered. Here´s 8 reasons given by some participants in my adult courses from the last 15 years...
"Deal with my anxiety in social situations"
"Become more confident speaking in front of groups"
"Think faster on my feet, because there are situations where I don´t know what to say, or think of it hours later"
"I am an engineer/accountant/lawyer/etc and I´d like to explore my creative side"
"I´m going through big changes/change of direction in my life and I thought your classes might help me with that"
"I did some improv at school ages ago and I really enjoyed it but never had the chance to do it again"
"My (insert significan other) signed me up as a (insert significant celebration here) gift"
"I´m ticking off a list of things I´ve always wanted to try, & improv is the next on the list".
// Glenn Hall