I believe all of the decisions we make in life can have an effect one another person whether negatively or positively, directly or indirectly. Most especially the people that love us and care about us.
I think it doesn't really matter if you are making a decision solely for yourself. For instance, if you decide to just feel happy today and block out all of your worries, then you carry a smiling face all around the place, you'd be radiating that same energy to the people around you and even if it is just for that moment, they'd be happy with you.
If you look at our lives as a huge mass of interconnected energy, you'd understand that each person is a link connecting to the other person. This remind me of an African saying, "Ubuntu." which means "I am because we are."