I do agree that happiness comes from loving & giving. And of course by interacting with positive people. But happiness per se is a subjective phenomenon. It is a misconception that some object or person can give us happiness for often we discover that the very object or person that we thought would be a source of joy & satisfaction instead becomes a source of misery albeit after a brief period of giving some joy . In a sense, our attitude & expectation from the object or person determines the happiness quotient seemingly vested in the object or person. We wonder what happened & start chasing some other object or person in search of the eluding happiness.
Even for food, the law of diminishing returns operates. The very same food that we crave for can become repulsive - depending on our state of fullness or how much we have consumed.
While it is important to add value to other people's lives by loving, giving & spreading positivity, we need to search within for true & lasting happiness, otherwise also called bliss which is a more intense form of happiness.