I fly part 91 and sometimes I am amazed at what I see 121 guys go thru. I remember once going northbound with multiple turns around weather in KC center airspace and an airliner (think it was UPS) reported MOD turb for just a min or two. He than said "I think we just flew thru the top of a thunderstorm" Like it was no big deal. I see airliners cutting thru lines I would never try. My B--ls are small!