The difference between a good casual post and a good advanced post is that 99% of the time in casual, even if a post is otherwise faultless and contains a very well realised character, it won't develop anything in any way. It'll be a static snapshot of what this character is thinking, feeling, and doing at this exact moment. The character at the end of the post will be identical to the character at the start of the post. And there's nothing wrong with this in casual.