I took four years of honors lab sciences in high school, and a year of honors chemistry, with labs, in college. I invariably did very well on the exams, and often lost a letter grade for the poor quality of my labs. I wish once, in all of that time (and we might as well add the lab courses from middle school to this), an instructor had bothered to tell us what the point of the labs was, because I was too hostile and paranoid to figure it out for myself.
See, I had it in my head from day one that school, through high school, existed to keep us busy. It was a bonus if we occasionally learned things, but that wasn't the point. Stay in line, stay out of trouble, turn in your assignments no matter how awful they may be, and next fall you will be someone else's problem.
With labs, I had the same attitude. I had read the textbook; I knew the FACTS, I didn't have to do all of the boring tinker toy stuff so that I would BELIEVE; I was perfectly happy to take the details on faith. And besides (influenced, no doubt, by this attitude), the labs usually didn't go right anyway. And then there were the thrice-damned reports, which always began with the idiotic words, "To prove..." We weren't proving ANYTHING, and we knew it. Sometimes the results matched the textbook, usually they didn't, no one really cared, just give me the damned test, I'll get an "A" on it, and we can stop bothering each other.
There are two things that instructors could have done to help (never solve; I was pretty much beyond that) with my problem. The first was to replace the stupid word "prove" with the much more accurate "demonstrate", because that is what we were actually trying to do, and I had an irrational hang up with verbal honesty in those days. The second was to say (admit) that we were not in the lab to LEARN chemistry, or biology, or physics; we were in the lab to learn lab techniques. Because someday, maybe, we just might find ourselves in a situation where we were dealing with real unknowns (or possibly industrial produciton work) where being able to do the process and get the right answer would matter.
Nobody ever said that.
Life goes on.