The single most destructive thing in any relationship is selfishness or self-centeredness.
Selfishness is being concerned excessively or exclusively, for oneself or one’s own advantage, pleasure, or welfare, regardless of others. Selfishness is the opposite of altruism or selflessness; and has also been contrasted (as by C. S. Lewis) with self-centeredness.
Nothing builds and sustain a relationship better than unconditional love.
To love somebody with no conditions or circumstances: to love completely.
Example: ‘I love that girl. Do I need a reason? no but I love that girl completely.’
Communication And Listening
One of the biggest communication problem is that we don’t listen to understand. We listen to reply.
In Stephen R Covey’s book, ‘7 Habits of Highly Effective People‘, habit number 5 states: ‘Seek first to understand, then to be understood‘. Live your life on this fundamental principle and you will never go wrong.