There's a really big difference between being a professional/ understanding basic business acumen vs being a pushover and being taken advantage of. 
There's a difference between extending a professional courtesy with a minor risk that you weighed and are okay with, vs having poor boundaries where everyone owes you money. 
There's a difference between deciding that you would really like to take an appointment short notice because it works with your plans/ goals vs allowing someone to dictate when they want to come all the time and inconveniencing you horribly. 
There's a difference between deciding that a business proposition presented is fair and agreeable versus letting clients get away with every discounted ask. 
There's a difference between a carefully calculated, intelligent "yes" and not being able to say "no." 
There's a difference between enjoying hard work for achievements vs jumping when told.