If you only love on and off like a light switch, you do not love others like God wants you to love. Jesus said, "If you only love those who love you what credit is that to you?" (Luke 6:32 NIV)
His point is this: all of us can love those who love us back. Becoming a master lover means you learn to love the unlovable. It's when you love people who don't love you, when you love people who irritate you, when you love people who stab you in the back or gossip about you.
This may seem like an impossible task and it is - that's why we need God's love in us, so we can then love others: "We know and rely on the love God has for us." (1 John 4:16 NIV)
When you realize how much God loves you - with an extravagant, irresistible, unconditional love - then his love will change your entire focus on life. If we don't receive God's love for us, we'll have a hard time loving other people. I'm talking about loving the unlovely, loving the difficult, loving the irritable, loving people who are different or demanding.
You can't do that until you have God's love coming through you. You need to know God's love so it can overflow out of your life into others.