Back in the 60's and 70's there wasn't an ability to "fix" flubs in the music studio, so bands had to be a very solid group of musicians to "nail" the right track. When those bands played live, and some of them still do, for me, it's magic. It's an experience to listen to a band that makes the live performance look effortless. Chicago is one of those bands. Here's one of my favourite all time songs, 25 or 6 to 4, Recorded Live: 7/21/1970 at Tanglewood - Lenox, MA.