More often than not, the warm fuzzy feeling you get from using a piece of software is NOT the result of one "mother of all features". Rather, it is the cumulative effect of a lot of little features - all of which add up to infuse 'life' into your software and give it a 'personality'.
You probably knew this already!
But when I got a cute little warning while using Gmail, I couldn't help but replicate the warning - to get this screenshot:
(please click on the image below - to see what I mean)