I'm not sure I've "learned" anything. You've largely convinced me that we don't really "know" anything but rather have varying degrees of belief, but I believed that to some degree before reading this site and am not 100% convinced of it now.

The most important thing I can think of that I would have said is almost certainly wrong before and that I'd say is probably right now is that it is legitimate to multiply the utility of a possible outcome by its probability to get the utility of the possibility.