Daniel; I feel for you. 20 years ago I had a similar experience, and felt the same way afterwards. I brought a beginner tree to my first ever bonsai workshop with a nationally recognized bonsai instructor (who is still around). I was naive, but extremely positive about the hobby. In a 10 minute period of time, this instructor personally belittled me to the point that I wanted to leave the hobby and never see another tree again. And to think I paid MONEY to be abused like that
However I stepped back and tried to put the emotion behind me. I evaluated everything the person said, and accepted the fact that it was all correct. I worked hard to improve technique and avoid making the same mistakes. The experience made me a better bonsai artist and made me appreciate how important it is to go to workshops, join clubs, and attend exhibitions, because this is an art form that is almost impossible to learn from books.
Now I try to take a more humble approach with my trees. I know that NONE of them are perfect - even the ones that make me happy. I have tossed many of my "sticks in pots" though I admit I still have a few for fun - either because I grew them from seed, or they are an uncommon species or cultivar.
However I am never embarassed to post my trees here - even the crappy ones. I always start the post with "here is a crappy tree - help me out". I have never tossed a tree because someone "told me to" but I listen to what people say and many times it has caused me to think differently about a tree than I had in the past. However I have not stopped being my own person, and doing my own thing, and if a certain stick in a pot makes me happy, I keep it. At the same time, I also know where I have to start if I want to show a tree in an exhibition in my lifetime - and it is NOT with a stick in the pot

So I also collect yamadori and pay decent money for pre-bonsai. I assume over time that my sticks in pots will all go away, and I hope that it will be due to the fact that I actually grew them into something