This is going to sound so cheesy and trite to most of you but fuck it, it's my personal experience and I feel strongly about it so I'm going to share it.
I have always wondered how it is possible to be happy on ones own or manufacture it without someone else. I find that strange. Is it even possible? if so, then I am truly defetive and need to die.
I grew up lonely. That kind of abject loneliness that comes from long-term isolation. No friends, no acquaintances, no one to talk to or interact with. I had severe social anxiety so the other kids at school didn't want to play with me or even have anything to do with me. This was my life all throughout childhood and adolescence.
Being aware that I had no friends and no family, not a single soul that cared if I was alive or dead, was sheer agony. I wanted to be liked so bad, I wanted to be included, I wanted to be loved. So. Freaking. Bad. The first time I heard that we don't need to seek love from a romantic partner I was floored. I kept thinking about it and I couldn't figure out what that meant and how something like that could ever be true for anyone in any circumstance.
Long story short, I got better through a ton of self-improvement work. I was able to experience a partner who was madly in love with me. That thing that I'd always wanted for as long as I was alive finally happened! Amazing, right? Wrong. It didn't change anything. It solved absolutely nothing, within me or in my external circumstances. I was still constantly seeking validation, approval and ways to keep this love and adoration. Deep inside, I still hated myself and regarded myself as unworthy of love and being loved didn't change that in any way.
Fast forward to more years of self-improvement. Now that I love and respect myself I finally understand what that quote means. I finally get it. Every human being is complete within themselves. When love comes from within, I'm no longer desperate to seek it from other people, I'm not needy, I'm not ruled by the desire to please others whatever the cost. It's still nice to have friends, it's wonderful to have a partner, it's delightful to connect with others meaningfully. But it's even better than before, it's more genuine... and it's practically effortless.
You're not defective if you don't feel this way. There's nothing wrong with you. Some of us haven't been taught self love and some of us have been actively taught self hate. We can learn self love and we can unlearn self hate. I don't think it's humanly possible to despise yourself more than I used to, so I can say with confidence that yes, it IS possible to turn it around. For me it wasn't easy and it took many years of very hard work but it was worth it. You CAN get there and you're not defective just because you're not already there.