Know that you are certainly not the only one who has done that before. I can think of one time for myself and one for Ross off the top of my head. I'm glad you decided to go anyway!
I had a flight back from Tiomila this year that left a month later than I wanted to. Noticed the night before and could change online with a fee. But oh man, that does happen to people all the time. Glad you got to go anyway!
I booked a Monday evening flight leaving the US Champs in New Hampshire a few years ago ... but thought I'd booked Sunday night. Was very confused when Southwest wouldn't let me check in 24 hours before what I thought was my flight time.
Worked out okay. Just missed a bit of work. :-)
You're right that many things can be fixed if you just throw enough money at the problem. It's great you were able to make the weekend happen. Sounds like you're having a great time.