I like to explain anything and everything if they're interested. I guess you can put that down to an enthusiasm for my work and the desire that everybody else should be as enthusiastic about it as well!
I try to establish the level of knowledge of the person concerned and pitch my explanations at the appropriate level. I feel that in some cases an good description of why something should or should not be done, for example, goes a long way to helping somebody who might otherwise just think we're following petty rules for the sake of it.
