The easiest habit for me is actually the half-habit: Play! I'm curious about a lot of things (I'm polymorphously curious) and find myself following a billion different paths of knowledge. (I often forget much of what I learn, but that's another story...)
The hardest habit for me is probably the using technology one, which seems counter to the half one, right? But while I'm curious about all kinds of other things, wires-and-gizmos-technology has never been one of those things.
Some of this comes from a deep belief that paper is the BEST technology for deep communication, both reading and writing. And I hate trying to figure out which remote I need to use with the TV, and which buttons I should be pushing in what order to make it all go. It just seems a lot of bother for a little bang.