I love second, Tricia, but I haven't taught K or 1st, so I don't know how to compare it.
They come in knowing the basics (hopefully) and then we just build from there. It's still hard for them though because we don't have as much downtime as 1st did, do more seatwork, don't give as much time for assignments, and there are no longer any guaranteed "fun" times as we hardly have centers at all and recess is used for make-up time if work isn't done.
I strive to make the lessons exciting, hands-on, movement-oriented and lots of read aloud, though, so I think they still enjoy themselves.
They do get a 50 minute period of PE, Computers or half music and half theater every day, though. But for us it's the last period.