What are some relationship "green flags" that indicate that the person is a keeper?

No matter how low or shitty I'm feeling she always knows how to make me smile.

I'll always remember our biggest argument to date, I was totally in the wrong, to be honest was being completely selfish, she has depression, and has done since before we got together, it's not always there, but when it is, it shows. And recently we'd been having small arguments over pointless stuff, but this one was awful. Started at like 1am and just argued through the early hours of the morning.

In the end it was all resolved, but what she had said (all truths, none out of spite) really hit me hard, and left me feeling really low for a few days, as I'd realised how much I was actually hurting her. She obviously noticed this, and realised that it was what we she had said that did this to me, which in turn made her feel bad.

A day or so later, we was just texting, general conversation, and I'd mentioned that I was having a gaming night with the 3 other guys I live with, and she turned up to my place with no warning, to drop off a snacks and stuff for us that evening. It may not seem like much, but I knew how much she loved me there and then, as even though I was completely in the wrong, and was the bad guy in the situation, she still made the effort to make me feel better.

/r/AskReddit Thread