Unpopular opinions (this doesn't need to be fandom specific)
(I'm just doing a few that have been on my mind lately, as I have a lot of unpopular opinions for specific fandoms but that would take forever.)
** This was talked about this recently, but I wanted to reiterate with more depth: as much as I love Firefly, I have long made my peace with its cancellation. I can understand the initial reaction since I was also with the "Firefly deserved another season" train for a while there as well, but over the years I've come to terms with it, especially since the reason why it rose in popularity was because of its premature cancellation and the dedicated fan campaigns that helped get it noticed. It not only got a feature film made because of that, but it also has merchandise and a series of comics that continue the story. That is more than any cancelled show has ever gotten. If the show had gotten more seasons, I don't think it would've been nearly as well-known or recognized as it is today. Firefly's success came from its cancellation. I don't want a second season, nor do I think it needs to have a revival or reinvention. If there is another attempt to bring it back on television, I would rather it be in the form of an expanded universe like Stargate, having cameos from the original cast but focusing on an entirely new story with a brand new crew. Otherwise, we should just leave it be. Moreover, I think many fans who still obsess over its cancellation need to let it go.
** I couldn't care less for the MCU or the DCEU. Aside from a few films I don't really care or connect with them. Marvel television, on the other hand, I actually really love a whole lot, I feel the majority of them have been underrated, since I feel more attached and connected with the characters and their stories, and it's why I'm incredibly bitter and pissed off that they basically cancelled it in favor of their MCU-based shows on Disney+.
** I'm just so tired of faux "woke culture" trying to push and dictate what I should consume and enjoy, this goes for fan culture and mainstream media, to the point when anyone claims that something is so diverse or progressive that you absolutely have to watch it (often with the "or else" implied to guilt you into seeing it otherwise you're not "woke" enough), I immediately get wary because oftentimes when you have to sell it that hard it's probably not as progressive as you think it is. Mind you, I used to fall into this trap as well. It's good to want to be inclusive and to promote and advocate visibility of marginalized groups in various entertainment mediums, we need more of this and to seek it out, however it's completely different when it's entirely performative where it's just ticking off a checklist to get praise and pats on the back for doing barely anything at all. Nowadays it just seems like there's this forced narrative for a certain level of "wokeness" that is very performative and manipulative to audiences, and in my opinion it's both counterproductive and insulting to actual genuine representation and equality in media.