There are a number of conversational cliches in the world of photography. Many of them are just demonstrably wrong, like "Olympus Color," or "The Leica Look." A few others are taken as damn-near gospel, even to the most cynical photogs.
Sharpness doesn't matter: This cliche is trotted out most frequently by Leica people who are trying to justify their hilariously overpriced lenses.1 But that doesn't mean that others don't fall back to this old canard. Anyone who is trying to defend their system of choice, even when said system has some lens that positively sucks, will try to argue that sharpness doesn't matter. It's how the lens "feels," whatever the hell that means.
Sharpness does matter and everyone knows it. Pixel-peeping is also more than a geeky pastime. By analyzing the smallest elements of the image, we can provide a semi-quantitative measurement for the later, full impression of the image. Anyone who has ever dealt with medium or large format film knows that all of that extra detail, even when printed small, combines within the visual field to provide an impression of texture. Only after pixel-peeing does one understand what this texture is or from whence it comes, and it is entirely predicated on how fine the detail is. Sharp lenses make images pop.
And that is only the artistic element to the argument! There is a large, practical argument as well. A sharp lens that extracts the maximum of detail from an image renders an image that is flexible. I have greater freedom to crop and cut the final image while retaining detail and texture.
The camera doesn't matter: This is something that I have only ever heard from internet commenters who want to think that they know what they are talking about.
It goes like this: person A asks "I want the best images. Should I get camera X, Y, or Z?"
Person B immediately answers with "It doesn't matter what camera, it's the photographer!"
This piece of total nonsense not only fails to answer the question, it insults the asker! Two birds with one moron. Said moron is doing this to show off their photographic bona fides, such as they are, and convince everyone that their "art" is just so damned good that they don't even worry about the equipment. The statement is not only insulting, it's completely wrong. If it was true, pro-level cameras wouldn't exist. We would all use cheap point-&-shoots.
For many environments, you need a very expensive camera to get the best shots. Wildlife and bird photography requires a lens the size of Ron Jeremy's naughty bits. Great landscape photography requires a giant sensor with the dynamic range of John Barrymore. Great portrait photography requires a lens that has an aperture the size of a dinner plate. All of these features cost lots of money. It is NOT the photographer; it is a synergy of artist and tools. Both need to be present.
*Insert Product Name* Color: Again, this tripe is spouted by someone trying to defend their camera company of choice. A very common one is Olympus color. I think that this is because Olympus has some cachet to its name and sells cameras priced within reach of enthusiasts. They then have to explain why they would buy an overpriced camera with a sensor that is always two steps behind the competition.
There was a time when color actually meant something. Lenses can cast very distinct hues over images, and a photographer's choice of film had significant effects on the final color of the image. Today, color can be set to whatever the photographer wants in a post-production program like Lightroom. There is no such thing as "color," anymore.
Three Dimensions: AGAIN, this nonsense comes from someone trying to justify their choice of camera system. This one is so abstract, so subjective, and so impossible to quantify that I essentially never hear it from those in the hoi poloi world of Canon or Nikon. Usually, this comes from an enthusiast who has bitten the bullet and bought a medium format camera. They now need to justify this purchase against those who bought a Nikon D3X and an entire briefcase of Zeiss lenses for the cost of a single digital back from Leaf.
Generally, a sense of three-dimensionality in a two-dimensional image requires shallow depth of field. This allows lines of contrast of varying degree to fade in and out and thus provide the eye with reference to infer depth in space. The larger the sensor, the more blur, and, sometimes, the more gradual the blur. But this is heavily dependent on the lens and similar effects can be had from a Canon or Nikon.
But that's not enough for these people! No! To rationalize the purchase, they claim extra dimensionality even when the aperture is set small enough to put everything in the image in focus. I don't think that I have ever heard this nonsense from top-pro photographers. They have medium format because they need massive resolution for their overly-glossy spreads in GQ, or whatever they do. Point is, they buy this for no other reason than to earn money. As such, they don't need to justify it. They need resolution; resolution costs a lot. It is a simple equation.
1: I don't mean to disparage Leica. I mean to disparage the people who like Leica. And not even all of them.