Seth had honestly felt bad about standing Christine up last weekend, but as usual it was a girl...and she was vulnerable and wanted to feel loved and he was happy to be the guy to help her with that. He had done his best to apologize, losing Christine was something he couldn't take, she was more important to him than anything. She was a saint for putting up with him and all his bullshit over the years, he was extremely lucky to have her and he tried to show her his appreciation whenever he could.
But deep down Seth still is the little dipshit he was in high school and tended to enjoy messing with her every now and again. So once he got to her house, take out bad filled with her favorite in one hand he pulled out his phone. He shot her a quick text saying "Hey, I know I promised to come over tonight..." he knew she'd freak and think he was bailing again. Holding in his laughter he knocked on the door holding up the bag next to him with a smile, waiting for her to answer the door and finish his sentence by saying "and here I am."