I was very lucky to get dropped into a General Science group in about the 3rd year (Grammar school) as I found 'pure' Physics & Chemistry a bit of a struggle. That did me a favour as I then had an easier O-Level, as opposed to two tricky ones that would have had experiments to do?! And I'd given up Biology after I think 2 years, we had to drop a few subjects due to scheduling problems?
I detested English Literature, due to the teacher involved, and the subject matter, which I think was mostly MacBeth, Far From the Madding Crowd (Hardy could be in the top-3 for the most tedious authors of English 'classics'?) and some airy-fairy poetry (I'm fine with Pam Ayres or Spike Milligan, etc!). Had they given us different books (say Wodehouse, Dickens or Austen?) I'm sure I'd have paid more attention and actually got that O-Level?!
Luckily I never had to work hard with Maths and English Language, the 2 key O-Levels (back then you needed 5 or 6 passes to get the better jobs).
Schooling is so subjective, due to the syllabus and teaching ability.