Or a parade-pisser, or party-pooper, or killjoy or what-have-you?
At times, in the past, I thought that being overtly cynical or critical would function like a defence mechanism where people wouldn't assume that I was naive and try to take advantage of me - but it could also backfire if taken too far, and people might even take personal offense to it even if I was criticizing some institution or some aspect of the status quo rather than any personal attributes. Or if I was in a group and they agreed on some sort of event, plan or opinion, I would be "devil's advocate" - maybe in some perverse attempt to demonstrate that I had some hidden wisdom or was looking out for best interests when others may have perceived me as lacking social sense. So ironically that just exacerbated things. "Live and learn"
I can say that I have on a few occasions in the past...and people would tell me to stop being so negative, or stop being such a pessimist - but beyond that, during my younger years like early 20s, people seemed to viscerally infer that I was some archetype of a disgruntled loner, or bitter loser, or what today they'd call "incel" (this was back in the 90s), even though my negative comment didn't have anything to do with women or dating - it's like they just picked up on some vibe that I was "other than" and my criticisms either caused or contributed to that vibe. Like we're talking situations where I disagreed with a majority opinion on an unrelated topic, or something that we'd planned together. Granted, there were also times when I criticizes aspects of the social structure or status quo out there which wasn't always welcome - where I said things like "there's no point in <insert action or attitude>, because the outcome is already predetermined thanks to <such-and-such circumstance or overarching interest that always prevails>."
I learned through reflection that generally speaking, whenever someone criticizes part of the status quo that tends to otherwise benefit the majority, then the critic is [subconsciously] regarded as a misfit, or that archetype of the disgruntled loner or weirdo or incel/loser who can't fit into their demographic's culture. Random example: when asked if I want to go with a group to a sports spectacle, then I criticize the notion due to "just surrounded by a bunch of loud-mouthed imbeciles who get carried away and become abusive, when it's just a frikkin' game" - even if the criticism may be well-founded, it wouldn't be welcome by some. I think this animosity becomes more pronounced when you try to include others in that criticism, that they too should act on it - people may interpret that as a "misery loves company" gesture where you want others to feel negative too. A more perverse example of this was when climate change activist Greta Thunberg had given a speech on the perils of climate change, being the archetypal "Debbie Downer", and then a prominent Canadian politician tweeted some vitriol about Greta being mentally ill, what she says can't be taken seriously and she just wants others to feel the same way as she does - anxious, upset, negative, in other words the proverb "misery loves company" personified.