re: How does Mad Men progress through the seasons?

Only one character (Peggy) has grown, although Pete has flirted with character growth once or twice. Rather, we see deeper and deeper into the characters. Don too, but to a lesser degree.

The last two seasons we've "jumped" further than the calendar suggests. Form 4 to 6, now everyone has long hair, facial hair and smokes dope.

ETA:

Joan's boobs got BIGGER, if you believe that.