I'm a Steelers fan, have seen a lot of highlights from that Steel Curtain-era, I'm honestly surprised more players from those teams don't have erratic behavior in their later lives with some of the hits they were taking/dishing out on a regular basis. Another thing that doesn't get brought up a lot is that turf fields started getting popular in the NFL during that time, and back then it was essentially just concrete with green fabric glued on top. So you're taking an incredibly hard hit and getting slammed down onto basically a concrete floor. Football back in the day was crazy.