Mel honey, I'd be pretty darned concerned that they had spent 'all day' trying to get her to sit. I'm sure they meant that figuratively, but even so, if she's not ready, she's not ready.

From everything that you've ever said about the Divine Miss M, she's one chilled out baby. Laziness is an adjective for adults, it doesn't apply to a small baby. When she decides that there's something to be gained by sitting up, that's when she'll devote her energy to it. Until then, she's devoting it to things that are much more important to her.