I like this reply, I think it nails it. You're there to show that you're a professional, so that's how you act at all times. If you decide the company isn't a

I like this reply, I think it nails it. You're there to show that you're a professional, so that's how you act at all times. If you decide the company isn't a great "cultural fit" then you can politely and professionally move on. Same with leaving a job in general. As soon as you decide to go there's no reason to not be as polite about it as possible.