When I was a kid in school the teacher once shared a simple formula which proved the curvature of the earth.
I of course set about using this formula in real life because I thought it was interesting.
Then I realized that I must not be remembering it correctly because it never worked. Not once.
Over the years I kept applying the formula and even looked it up to remind myself of the proper method of calculation.
Still it failed to work. My frustration caused me to question and wonder why I just couldn't seem to get this simple calculation to work properly.
...and so time and time again I would just shrug my shoulders and let it go. Just forget about it for a while with annoyance at my continued failure and ineptitude.
Then a few years ago I began finding information about flat earth on the internet. At first I thought it would just be an amusing topic but then quickly that turned into a " Hey wait a minute" moment and got my greater attention.
These days there is plenty of information online relating to this subject and I won't waste my time trying to convince anyone since it's not important to me if you understand it or not, but in case you're curious here are a couple of links for your perusal.