It is scientifically proven that the people we love most are the ones who hurt us the deepest.

I have found this to be painfully true.

I had a friend once, a very close friend. I haven't seen her in months, but you can see proof of her impact on my life through the scar she left on my back with her knife.

Here's what happened.

She was a bright, spunky, free spirit that was as sweet as could be. Or so I thought.

That was before I got to know her a little better.

As time went on, her true colors bled through the papier-mâché act she put on for the world.

It started small. We'd go out together and meet really great people that seemed to vibe so well with us. Then we'd get home, and she would say all these awful things about them.

It always threw me off because she seemed to genuinely like them when we were with them, only minutes before.

It became more strange when we'd see them out again, and she'd act as if they were best friends she'd never spoken ill of at all.

I brushed it off as her not wanting to hurt their feelings.

Until it soon became apparent she had zero regard for anyone's feelings at all.

She met a boy, a beautiful boy with the kindest heart and the purest intentions.

The night we met him, when we got home, I told her how attractive I found him. And she told me he wasn't her type. Fast forward to a few nights later when I saw them making out at some party we were at.

She was all over him.

Now, before you label me as jealous that she got the boy I found cute, let me set the record straight: I simply thought this boy was attractive. Nothing more, nothing less. I had my own boy troubles to keep me busy.

What bothered me was the way she acted.

She would be all about him when he was around, but as soon as we were alone, she would tell me that she wasn't into him and that she didn't understand why he wanted to pursue anything with her.

I was dumbfounded.

The way she acted with this boy was something you'd expect to see in one of those R-rated spring break movies. It was almost too hard to watch without vomiting.

And it wasn't like they were just hook-up pals or anything. He was really into her. And she acted the same way to his face.

On top of that, she was also running around with other guys — including her ex-boyfriend!

But I never uttered a word. Not to any of those boys, or to any of my friends. And I always listened and sympathized with her when she talked about her boy troubles, which was more than I could ever say for her.

When I did have problems or need help, she was nowhere to be found. In fact, she told me she didn't want to be a part of my "drama" because it was too much negativity for her.

That's laughable, considering every night she was ranting about a fight with her ex or her parents or why she couldn't stand this mess of a love triangle she had made for herself.

Luckily, I found a better friend group that I could escape to.

In all of our time together, after everything I witnessed firsthand that she would do other people, I had never once said a word against her. Not to her face or to anyone else.

However, that didn't stop her from driving a knife into my back the first chance she got.

She lied about me. She did things to intentionally hurt me, and she would lie about it even when I had proof of it coming from her lips. She was selfish and intentionally caused other people harm without a second thought.

And I never heard her utter an apology. She had a special way of guilt-tripping others into thinking they were the ones at fault, and she would sit on her high horse as their apologies inflated her ego even more.

I never thought when I met her that she would hurt me as unapologetically as she did. I never thought her knife would cut the deepest.

And I never thought that, even with her hand holding the knife in my back, she'd still have everyone fooled into thinking she never laid a hand on me.