Being single in youth is not a big deal. You're in the mix of academics, jobs, personal problems, and so much more.
But when you're in your 30's, or 40's, solitude sinks in so painfully. Do you not wish to have someone to hold at night? Do you not wish there was someone there to cry and celebrate with? Do you not wish you had someone who despite everything you've done wrong, will always find everything about you beautiful?
Love is one of the reasons for happiness. It's not overrated at all, it really is as spectacular as people put it out to be.
The point of life is to procreate, but humans have made it to even more than simply reproduction, it's a social structure that two people can share happily or in peril, depending on how they choose to.
The thought of dying alone is much of a reason why love is very important.