I agree with just about every point on this thread, although I'm in the camp that thinks "nobody cares" usually means that you don't need to worry about what other people think in most cases.
For funerals, for example, as long as you wear a smart, sober outfit it won't matter that it isn't black or didn't cost the earth. It matters more that you are there to support the bereaved.
I tend to notice outifts that look fabulous or are inappropriate for the occasion like stilettoes on a country hike and, sorry, outfits that are deeply unflattering on the wearer, although I would never say anything to them.
I admit to wondering about a couple of things though.
Trainers - the angst about branded trainers or trainers that are "in" just baffles me. I just view trainers as a practical solution for something comfortable to wear on my feet, not as a fashion accessory. The sneering I see on trainer threads at people who prefer to wear deeply "unfashionable" brands (Skechers, for example) is unpleasant and often ageist. If you removed the logo from the top fashion brands and some of the more trendy looking "frumpy" brands I reckon that people would struggle to tell the difference.
Bags - again I just view a bag as a practical accessory - Is it big/small enough? Does it have enough compartments? Is it waterproof? Does it close securely? Is it good quality? etc. I would want a bag that fulfills those functions, but I don't care if it isn't a designer bag that costs four figures because bags just don't give me joy they way a new item of clothing that flatters does. However, I don't post on bag threads with fatuous comments like "you could go on holiday for that"