Things like chance meeting, corner-eye glimpses, caught-eyes-across-rooms, or perfect comebacks/insults that you thought of on the spot and delivered in a timely matter - not 3 hours later in the shower. (my shower-arguments are the most creative, inspired things you would ever dream of; should they occur in time there would be no recourse).
So, when such chance occurances happen in real life - they delight me for days. They never have the same meaning, of course - that person you eye-locked with in the supermarket just thought you a weirdo, really; but the occurance itself -
merriment for days.
God but I love coincidences. And I love that a couple of you know exactly what I am speaking of.
EDIT: So there's been some confusion - the 'eyes caught across rooms' thing is in bold italics to draw attention to the Lizzie/Darcy example, not mine. Let that pickle your noggin.