Good question!
I'd say for me its the intimacy. This close look at some thing in the front gives me the impression of being very private with my object of interest. Here, it's crystal clear for me, the small distance is like a lover I engage with. This is focusing. But: this closeness does not blind out everything else. I am still aware of the background and in fact, if you would cut it all out and just leave the close up, it would loose all its charm. It transports for me the intimate relationship towards the close and at the same time the relationship to the external. Never forgetting that there are things out there I do not see clearly yet but of which there is the promise that I can experience them one day. The blurriness is the factor that makes it kind of mysterious. Things I cannot identify in a second attract the viewer as wanting to find out but at the same time satisfied to not really knowing.

I went a little far with that. But hey... you asked :)