What can be a red flag for you not to work with clients?

[Btaliat]

There are more than enough red flags for the freelancers that are very smart. That's why it is always better to be smart in order not to secure tasks from clients that will later turn to issues. Most times, there are some clients that have bad rating. Previous freelancers didn't rate them may be because they don't pay on time or they always complain on one thing or the other. What are other red flags you are considering?