Just another learning process

I heard from my friend that sometimes, people that you think is an important people in your life, even you are willing to do anything to help them in any condition and always put them as your priority, THEY JUST DON'T CARE about you or they have their own priorities in their lives, and maybe you're not even make it to their top 5. To accept the fact that they won't be there for you like the way you were there for them, it's quite difficult. Because you think you have them who will always support you with just saying "everything's gonna be fine" or maybe "keep calm, I got your back. But I learn a lot about it, and realize that I will be so mean and selfish if I judge them just because they have their own perception about whom are important in their lives.