Don't make someone a priority, when you're only their option

In order for any relationship to work, both parties have to make/put in effort.  It's extremely unfair to assume that one party will always go the extra mile, make the sacrifices, make the time to make the relationship work.  Because when this continuously happens there will be a moment when said party just says "damn, why am I the only one who goes out of my way for this person (these people)?" And then they won't.