I'm used to a drier climate. When I've visited some places that are more humid, I've been surprised how much more I can smell everything. Every person. Every place. Around corners. What's on the ground. Everything.
I do wear a scented antiperspirant because I like how it smells, it doesn't react badly with me and I don't wear a lot of other scents. But yeah, some places require more than that even.
Ego has been mentioned. Sunk cost fallacy plays a part. Combine those and people tend to over value the effort they've made to form their opinion, either through some form of information consumption or synthesis of known ideas/held opinions, while devaluing/doubting the existence other people's previous efforts. So, you often end up with two people who both think they're informed and assume the other person is just making up an opinion right now and failing to see their valuable insight.