[noisy_boy]

The question is not of good faith or the competition being overt or malicious type etc. Time is finite - if you are spending on one side, you can't be sending on the remaining sides. Usually the people in your life realize it and adjust for the priority/greater good and so yes, they will willingly sacrifice in that spirit. But the relationships themselves are emotionally competing - if you have, e.g., to choose between relocating for the future of your kids and your ailing parents, those duties are competing, even though the recipients themselves may not be - you will have to choose.