Most people do not follow their own advice. You see these people everyday. It is a sad sight to see. You notice something off about them. Something isn't right. When someone puts others before themself, they have to lie or make promises they cannot keep. You would not put your full trust into this person.
You need to realize we are all human and are inherently flawed. Saying "No" to an idea or person can be so freeing. So put yourself first and make your needs number one.