At the end, when Tim wipes up the spilled perfume with the red dishcloth, the dish cloth has moved during the time he answers the phone and when he returns to see it smoking. BH.
Just after Tim looks at Jill and the boys through the window in the backyard a microphone is visible when he speaks to Wilson.
While Tim and Al are shopping in the women's department; Al is asked if he prefers big women. He says that his mother "was a big woman". Al's mother doesn't die until the last season.
Jill's Birthday, her birthday is set during the winter months because the characters are wearing coats. In Jill's Surprise Party (#5.4) Jill is going to see her cousin about the piano, Jill is wearing a short outfit with no coat, it seems to maybe her birthday is set during the spring or summer months.