This is my third building experience and probably the most stressful. Most of it was a breeze but I ran into a couple small issues:
Screwing the mobo in, two of the screws did not want to thread straight. The solution was to get angry, throw caution to the wind, and crank the screwdriver. I went through this twice because of my second mistake...
While installing Windows I discovered my IO shield had a metal piece bent in front of the ethernet port. Double check your IO shield before screwing things in, folks.
HDD cage has a preinstalled screw that will not loosen. I was able to fanangle my drive in there without removing the cage, though.
Overall it went fine and I'm happy with the results. I can't really speak to how the hardware performs just yet because I'm not currently playing anything particularly taxing. Rocket League performs buttery smooth and temps seem normal, so there's that.