Can I stay too long in a coffee shop?
Why would you want to stay too long in a coffee shop?
It's good for me to have more time to spend with strangers
I agree that you would benefit from being among strangers rather than being alone, especially for your mental health.  It's even better to do it somewhere you enjoy, so continue staying too long at the coffee shop and you will improve socially over time.
I'm going to stay too long, order up more coffee, and make everyone hate me.
I don't think that people will hate you if you're ordering coffee? It would be a good experience for you to stay in the coffee shop as long as you'd like if you're enjoying yourself.