Bad clients are like heroin addicts
A heroin addict will tell you they love you and then when you’re back is turned they’ll rob your wallet/purse. They’re only after one thing.
If you have a client that sucks up your time and pays badly, then they’re not interested in you and thinking that you can solve it by being a better provider, then you’re on drugs.
If they think that they can get better value by having you look at something in your free time, when your time is most valuable, and pay you least of all because they really can’t afford to invest in their own business, then run.
They’re robbing you and you’re just forming the other part of a co-dependency relationship.