That there kids are financially and physically well and happy adults even if they don't call them, visit them or meet them?
Now that my kids are young i feel, it would be enough for me, but i don't know, how i'll feel when i grow old.
You feel this way because your kids are still young. And young children are DEPENDENT upon their parents for financial, physical, emotional well-being (food, water, shelter, clothes, education, moral guidance, health, etc). They can't survive on their own, and since these things are your PREDOMINANT concern now......you feel content if these requirements are met. Your needs will change as the relationship with your children evolves.
When your kids grow older and more independent........and are able to fulfill these requirements ON THEIR OWN..........you might wish that they'd take out some time to spend with you. I think it's human nature for everyone (including parents) to desire consideration in others. Nobody wants to feel like a machine that was "used." I don't know if that makes sense. People are more than just providers...........they have feelings and emotional needs. And that's what parents teach their children along with fulfilling their basic needs. They teach the importance of having sensitivity and consideration for others. Without these qualities, life becomes robotic and brutal.