In my past 4 years of heavy flying (100k domestic miles a year or so), I've had one diversion. Happened a few weeks ago flying LIT-ATL. Were 20 mins into the flight when we turned around to go back to ATL. Hit a bird on and it had damaged the front landing gear doors so they wouldn't close.

Multiple medical emergencies in the air, but all were resolved in the air and we continued on.