Yes. I did great at Standard grade and was on track to get A/B for everything that I did at Higher. Ended up with BBCD. Two lowest were my best subjects throughout the year.
Now finished only two Advanced Highers and they were very mediocre. I obviously didn't learn my lesson. That, and exams are the bane of my life.
I honestly think I could have done great at school, but I didn't. It's something I will regret for a long time. I might re-do my stuff at a college so I can (try) get into a university that doesn't suck.