There are a couple of ways to get oneself over this hurdle. There are "long stories" behind each thought, but, they do make a difference.
The first thought is how many finished models do you have on your shelves? If you only have a small number of finished models on display, but, have a large number at the "90% finished, but hiding in the box" stage, then you probably have better quality builds waiting to get done than what you have on the shelves. This turns around and can become finished models when you realize that each newly finished model will raise your quality level of models you have on display.
Another somewhat related thought is how old is the oldest model you have on display. I don't mean the physical age of the molding, or the purchase date of the kit. I mean which build is it? Do you have your tenth model finished ever, on display? or your 50th? I am willing to risk money that if you have something you finished ten years ago on display, that you have improved your skills on each of those models you have hiding in boxes. And with just a little care to finish one of those at the same level of quality you have put in so far, you will have a "better" model added to your older ones. After all, how many models did you build to the "90% level" since the 5th oldest on your shelves was finished? You might be "40 built models better at modeling" today, and just not realize it.
I was stuck in a place that made me want to do all of my models to the standard of one I finished about 15 years ago. It had all the "great things" we want, "snobby paint"-aftermarket decals and weapons, it was an expensive import kit, etc. I was trying to build all of my stashed kits up to that level. Anne looked at my stash and made a comment about "who is impressed with all these pretty boxes?" one day,,,,,,,,,,and now I have realized that I am the "best modeler that is ever going to build my stash"
And every finished model looks better than my "1st model ever built", since it sits on the shelf with them. And I don't worry about getting them better than the "great things" model, since I don't use all of those things on every build.
Rex