I haven't made too many blunders while building, not recently.
Some of my 'cockups' include not waiting for the paint to fully dry (or glue) before handling or assembling tiny parts. Impatience with decal application, that's a good one.
Probably one of the 'shortcuts' I paid for came when I was about 16-17. I was building a model of the Aliens Dropship. Missile pods out, ramps and stairs lowered, It looked pretty sweet. I decided to use "krazy glue" instead of normal modelling glue. I thought I would save time. I could have the whole thing painted and assembled in an afternoon (I can still underestimate the time required for any given project, so it's nice to see that hasn't changed with age).
It was a toss-up between "the glue would not set" and "you've used too much, too many times now, that it's eating away at the plastic."
At least I realized quickly enough at one point that if I forced the issue, I would have an unrecognizable lump of melted styrene, nicely painted.
So back to the old (standard) glue, and that did help rescue the situation.
Lesson learned? There is often no such thing as a shortcut. If it worked, it would just be the way