Looks like a nice site!
First I want to say that you have the ability and apparently the confidence as long as your wife was spotting for you!
Now you learned that you can do it with out a spotter and I prefer that method, although when I am backing into a spot I have her get out and stand straight out from my right hand side so I can see her and her only to is to watch for obstructions above or behind or on the side! I take care of spotting the RV for backing and watch the left side as well as her but I stop when I move my head to check on her. Basically she is where she is at to keep her from getting in my mirror as passengers seem to want to use the mirrors when backing up also!
Your right about not getting over confident! You will, like all of us have days where the juices just aren't flowing in the right direction and you have to make extra moves to get into a relatively easy spot!
To me, over confidence is saying I can get into a spot that may be a bit hairy , only to see once I try, I might have been "all hat and no cattle", but I will conquer it with effort and patience!
Complacency is when accident happen! Just when you think you have the process mastered and you have been in that spot many times and in your mind, you could back into that spot with your eyes closed! And then it happens! Some one moved the picnic table in your path or you back in too fast and you hit that rock beside you, or that tree you always avoided some how moved right into your path!
I have learned to talk to myself when I approach my site and then before I start my movement, I tell my self where I want to put the tires and where on the site do I want to end up, more on the left of it or the right of it! I do a walk behind to survey my surroundings and then make my move!
Even with that, I got distracted last year and had a different type of incident that nearly cost me my right arm and ended up with 3000.00 damage to my truck!
Anyhow, nice job on getting into that excellent looking site!