I didn't have the same take on Joan that you did. For starters, I think her reaction to the time card came from jealousy. She used to be the secretary who led all the bonding between the women, collecting money for birthday gifts, etc. She pushed the women, and made sure she was the queen bee. But she was also adored by them as the one who looked after them. Seeing another woman filling that role made her realize that she's got other responsibilities now, and has had to give up the "fun" roles. I think that is why she lashed out. Then, when Harry made an issue out of her being a partner and having the power she does, she realized she will continue to be in a tough spot. The partners understand why she has the role now, and know she deserves it. But the outsiders don't know the circumstances. She's left with the choice of either admitting that she literally slept her way to the top, or accepting that people will always question why on earth she is there. She can't win either way. I think all of that made Joan realize she has all the headaches of her job, but has lost all the fun perks. I think that she passed over the keys to supplies and time cards to embrace the "fun" that her job now offers her in delegating the worst headaches to other people. She found a way to shift the responbilities that make her disliked to other people.