So sick of not trying

I was invigilating an exam recently, and apart from spending a bunch of time remembering how to play This Charming Man, I realised that ever since I was at/finished school I've been saying something along the lines of "I would've done alright if it wasn't for...." or "not too bad considering......" Which is pretty poor. It was sparked by thinking about GCSE science, and how I managed a couple of B grades (that's almost an A!), despite my coursework being either shit or non-existent. Or both. And this pattern has continued. I'm very much reminded of something I read/heard about fear of failure and procrastination. Like if I'm not invested in something properly, and leave it til the last minute, or just don't try that hard, then I can tell myself it doesn't matter if the end result isn't great. I don't think I want that to be the way my life plays out. "Not too bad, considering" is no legacy.