Very underrated & taken for granted by fans. I know at times I've taken it for granted & at times been utterly bored by it, due to 30 years of it being held up as the representation of "the only thing Michael Jackson ever did" by the critics & media. Let me be clear: not bored by Thriller as a work of musical output, but by Thriller as a notion, this thing that people could use in a passive way to disregard everything else "Michael Jackson" without really knowing, or listening, or hearing. It became the predictable cliché from which the music press would bang over the heads of everyone whilst reviewing & rejecting subsequent albums, films & books etc.
The album became the be-all & end-all, the get out of jail card for musos on tv show panels when asked about MJ or pop music. I'm only speaking for myself, but I did get so tired over the years of constantly hearing or reading about nothing being as great as Thriller, & possibly, my way of rejecting these claims was to ignore the album, I was "a fan" and therefore, to a degree Thriller was only for the casual music listener, the ground floor entry level, or for the music critic who's mind was already made up about anything that came before or after, whereas I, as a fan on the inside had a whole world of incredible music, short-films etc that was equally as genius, sometimes even better.
It annoyed me that the theory was "the short-film Thriller was unsurpassable", even if this or that was better. I Think the other great misunderstanding about that album was that it was more than just an album per-say, it was a fashion accessory, a statement, to own this record on vinyl in the 80's was a measurement of cool, like the rubik's cube. In this day & age you have the i-phone, that thing that's become a statement about you, (who you are) or a status piece. Well Thriller tapped into peoples imaginations in that way, & subsequent albums that still managed to sell an unnatural amount, in there tens-of-millions were deemed "not a success" or in the case of ten-plus million for Invincible "a flop" which could not be further from the truth. Thriller has always been "that album" for good or bad. I listened to it recently and was blown away by it's brilliance.