The worst things are fountain pens. My parents told me I can't write with them properly because I'm lame. It turned out 30 years later that those are for right hand only by design, and only top quality ones write properly if you push it on the paper. Of course we didn't have one of those.
I'm a lefty too, I recently found the Lamy safary has a left handed version that I can actually use ! Their ink also dries rather quickly, so if you whish to give it a shot again, it's been night and day for me. Much better than the overpriced crap they sell in general stores that I could never use, or that would simply go through the paper thanks to highly diluted ink...
My father is left-handed and has a lot of similar stories. Things are slightly better these days than they were in his time, but the world is still designed for the right-handed.
The training I did only taught "the right handed way" despite me being a lefty since that's the only "correct" way of using a chainsaw. If you learn that way it becomes natural, like using a mouse right handed.
If i pick up a chainsaw without thinking about it it immediately feels wrong and a switch to right hand grip.