I am typically really not a fan of images like this, they just don't tell enough of a story, or invite enough imagination to hold my attention.
That said, I really like this one! A lot of it has to do with the color range, which keeps it in a very muffled, sleepy tone. I'm at work right now, and looking at this literally made me sleepy. I'm not sure about daydreaming in the sense of bubbly, happy daydreams, but certainly those of a more foggy, swampy, textureless variety.
This is entirely a personal note, but this is one of the few images I've seen on TPF that I'd actually buy a print of if I had the money.