K.V.
My almost 20 month old daughter does the same thing. I pick her up at 11:15pm though (because I work 2nd shift) and she is the only daycare kid there at that time. After she runs up to me to greet me, she will want back down to continue to play or chase after daycare persons husband or the kids (specially now since they are home for Christmas Break).
It gives me a big sigh of relief knowing she loves it there.