What the hell is wrong with people?

So I had plans to go over to my new "friend's" house today. She called last night and asked me if I wanted to come over then, but since I knew I would be there all day today, I declined. Then she confirmed once again that I would come over today. I said yes, in the afternoon. She had contractors and stuff coming over today, so she told me anytime, including the morning. I told her I needed some time to get some stuff done but I would be there in the afternoon. It's a 30 minute drive to her place and I'd never done it before. It was easy and I was relieved when I got there and spotted her car in the driveway. I rang the bell twice. No answer. So I knocked. That set the dog off, but again, no answer. I knew she had a big garden in the back, so I went to the fence to see if maybe she was out there. Didn't see anyone. Rang the bell again and knocked again. Nothing. So I got in my car and left. I saw the curtains move, but that could have been the dog. I called her on my way home but got the answering machine and so far, no calls back. What the hell!!! Now I know I didn't call her before I left, but when someone tells me they'll be home all day and to just come over whenever, I take them at their word. I don't know what to think now.