There Don sat on the grass, barefoot and cross-legged. This can't be how Mad Men is going to end, with an effing tribute to the calming powers of yoga, thought everyone watching. But instead of a classic Mad Men slow pullout, the camera pushed in on Don's face. And like that, a chime rings and Don smiles.
We were introduced to Don as a man alone in a bar trying to think of a great idea. And after 92 episodes, and plenty of good ideas (and a few bad ones), he finally thought of one.
It was a smile not unlike that of Walter White's at the end of Breaking Bad. Both were tributes not to great ideas, but the meaning one finds working to create them. They are tributes to creating the shows themselves.