"Two are better than one, because they have a good reward for their labor. For if they fall, one will lift up his companion. But woe to him who is alone when he falls, for he has no one to help him up. Again, if two lie down together, they will keep warm, but how can one be warm alone? Though one may be overpowered by another, two can withstand him. And a three fold cord is not quickly broken." ~Eccl. 4:9-12
When our acquaintances become friends, and then our friends turn into close friends, we start caring about one another in a different way. We share our happiness; even if we are sad, the other person being happy is enough to make us happy. The happiness gets shared! :D
This is not just talking about our non-blood related friends; but our blood related friends as well. Whether it be your child, spouse, parent or sibling share some of your joy with them!
John MacArthur notes on this passage that "Life is better with companionship". I believe that this kind of companionship is especially true of the marriage relationship: the person you choose to love for the rest of your life. If God has already put that person in your life, thank Him. If not, pray for that person, whomever they may be. Just because you don't know who they are yet does not mean you can not pray for them! :-)
"There is a friend who sticks closer than a brother." ~Proverbs 18:24