None of the books I studied at degree or MA level (languages and history, but with a strong literary focus) count as my favourites, and if they were my favourites going in they certainly were not by the time I’d analysed them half to death and wrote countless essays on them.
My actual favourite is Wuthering Heights, has been since I read it at 11 and barely understood a word, I just loved it. I’ve read so much since about what a terrible book it actually is by people who really dislike it, that’s fine, but I love it and always will. Another favourite is Pride and Prejudice, read at a similar age and loved fiercely ever since - but sounds like a terrible cliche when I state it as my favourite.
I also have ‘kids books’ that remain favourites in the Anne of Green Gables and Emily of New Moon series by L.M. Montgomery. I reread all the Anne’s recently and loved them all over again.
I read the HP books in my 20s, I remember the excitement of getting my hands on the new one the day it came out and spending the entire day immersed in that world. I can see why they would be people’s favourites, I certainly loved them though I’ve felt no call to reread them once I finished the series.
It’s not like she named Sweet Valley High (they were definitely my favourite at one stage though!)
Also, there’s a lot of sophisticated, thoughtful and groundbreaking tv being made these days which I very much appreciate but if you asked me my favourite ever series I’d have to tell you Dawson’s Creek, or maybe The O.C. In fact I still keep my O.C. DVD box set s despite no longer owning anything that plays dvds.