I learned that I LOVE making things go boom with my Asari adept.
That sometimes when you are more than one person on a mic and you sound like you're having fun, someone else will plug in a mic too. At least twice yesterday it happened that we started the match with two people on mic and ended it with four people on mic.
That I am not as sucky as I thought I was. Before the weekend I was hesitant about playing silver, because I tend to worry I'm not making a difference, or holding the team back. Now I feel like I can play gold without feeling I am the team's very heavy pet rock. I'll still mostly play on silver and bronze, at least for the time being, but now when people ask if I want to try gold with them I have the confidence to say yes.
That even when you tell people something like, as an example, "you spam warp and I'll spam throw", and they say "okay", there's a good chance they won't actually use warp, at all. The entire match.
That it's not always a good idea to listen to the advice-givers on mic. Sometimes they give bad advice. Sometimes they give textbook advice that sounds good in theory, but doesn't actually fit the situation you're in at the time.
That people who don't read the forums aren't always willing to listen to suggestions like "how about we try taking out the smaller guys first and leaving the banshees and brutes for last, so that maybe we stop getting 18 of them each wave, and maybe we stop getting out arses handed to us by marauders and ravagers?" or "can we play against reapers, because there's an operation this weekend". (Never hosted as many games before as I did this weekend, just to be sure we played against reapers.)
That I feel really bad when I kick someone. (Unless they are selfish and/or rude prats.) Twice this weekend we kicked a random because a friend wanted to join. Both times we apologized and explained, and both times I felt terrible.
And finally, I learned that I hate marauders, with a passion. Last match I played yesterday was on silver, and I used my last missile on the extraction wave to blow up a single marauder who stood nearby. Seeing him disintegrate was the highlight of my weekend.