Roger shows a strangely warm concern for Don's well being.

They both served in the military and then went to work at an advertisement agency, keeping the Sterling family tradition of having a father and son working together in the family business.

They Both are black.

Just my two sense, and why did she always check her bag before she left, all she had in her purse was a ball of aluminum foil her son would play with.

You guys ... it's been so obvious all along! I guess I was caught up in that whole theory about the opening sequence showing us that Don commits suicide, because I didn't catch it even after 134 rewatches. Bobby was right all along, we were just too blinkered to listen to him.

She's always creeping up on people trying to have a good time. Roger and Marie. Don and that doctors wife. What's wrong with you, young woman? This room is occupied!

I found out the man behind lucky strike “it’s toasted” ad wasn’t actually called Don Draper. In this case the show is alternate history, right? Where another ad man curiously has the same idea? Unless Don steals it and pretends to come up with it by himself.