Flying ORD/MLI tonight & we are delayed by over an hour because GA says crew wants to take a break between flights (as he shook his head in wonderment). Crew arrived about 15 minutes after scheduled departure time. I've never heard of this. AFAIK once the crew arrives the flight should be prepared & ready to go. The irony is that's it's a 50 minute flight gate to gate. Couldn't they rest afterwards?