I still love playing 3, but I also love 4. I get more frustrated with 4 as I get fed up with chasing them around to make sure they're doing what I instructed. The water drinking, the getting down and doing push ups, not sitting at the same table when out to name but a few.
If I could merge all my favourite bits of 3 into 4, it'd be a perfect world!
For example today; my toddler wouldn't do as I wanted and her mood was horrible. I tried making it better, but no, off she went doing her own thing which made her angrier. I got her mother to fulfill her needs, but no, they got cancelled out so she'd go off and do things she wanted to do, with no interest in looking after her daughter. SO annoying!