Highpoint: I missiled the corpse of a Marauder and it felt really really good. I see your elbow of doom and raise it. All in. 
Lowpoint: A frustrating wave 9 trio wipe on Goddess against Reapers. It came off the back of the utter destruction of Reapers on Rio using a TSent with Lancer. The host was reasonably experienced but using a level 14 Asari Huntress and seemed determined not to use consumables in either game, and I quit the lobby second time round. But when I found myself back with him again I stuck around because he had shown himself to be a good enough team player. I would much rather have waited for a full squad though, because it was pretty obvious that I was going to be taking most of the heat - the other member of our trio was a very low level TGI, but at least he/she was using consumables. Seriously, if you're playing a Huntress on Gold, put some Warp Ammo on at the very least - it might have made the difference.
The other game which stands out started out as a duo on Hydra against Geth. I was an SI again, with a Krysae this time. The other guy was a high level Jugg with an ADAS. Talk about a grumpy Jugg! I figured that as a duo, it would make sense for me to shadow him, to some extent, but oh no, Juggy didn't like that, and spent more time on wave 1 shooting me than the Geth. I took the hint and left him alone for most of the match, including the times he died. If I could play it over again I would never have left his side and spent my time exploding Geth in his face, as he didn't bother his arse helping with objectives, and used 5 missiles on extraction. I imagine he felt genuine pride that he topped the scoreboard by a whopping 2000 points. If we hadn't been joined by a couple of Krogans I would have quit and left him to it. Why do these people not just solo?