Why do you feel you need to convince them of anything? I totally get having your eyes opened to the broader spectrum of coffees available but end of the day it's a preference based on subjective senses. Let 'em do them, what's the harm?
Coffee
โ - The hot beverage that powers the world!
Coffee gadgets - It's always great to learn about new gadgets. Please share your favorite hardware or full setups. It might inspire newcomers to experiment!
Local businesses - Please promote your local businesses. If you are not the owner of the business you are promoting, kindly ask the owner if it's okay. It would be great if the business has a physical store to include an exterior or interior shot.
Welcome to boomer psychology 101: you scream at them very hard and they will scream back and keep their position, but after you have left they will change their mind
Welcome to asshole logic 101- you must scream at people for absolutely inane reasons, such as their coffee being "too bitter".
how do you convince someone that bitter coffee is not good coffee?
That's the neat part; you don't.
Without judging, some people confuse bitter for strong. You should try brewing their coffee different ways that will make it intense, but not bitter to see if they like it better. I'm not an expert, but maybe Chemex? Aeropress? Pour-over?
That's all you can do if they end up preferring ~~butter~~ bitter coffee!
Let people enjoy things, man.
Simple, just respect their taste. I had friends who grew up with instant coffee and they hated even the best brewed coffet I could make..