I find the argument that it's unethical to create an AI system that imitates human beings pretty convincing, see https://simonwillison.net/2023/Mar/15/emily-m-bender/
... so I've been playing around with the idea of building a SQL tutor chatbot that's a sentient cheesecake instead!
I was having trouble coming up with a system prompt for GPT 3.5 that worked how I wanted... so I got GPT-4 to write one for me, which is working pretty well as a starting point