All opinions are subjective, FTFY.
If you want to get philosophical about it, one could argue that everything we know, think and perceive in any way, could be described as fundamentally subjective.
We certainly know that our perception of color is a product of a particular type of processing in our brain. When we see a leaf on a tree that is green, that property of greenness is not a property of the leaf but a property of the way our brain processes a particular frequency of light that the leaf reflects.
One could also argue that the above point of view is silly because a green leaf, if it's perceived as being green by a normal person who doesn't have color vision problems, is green because it reflects a wave-length of light in the range of 530 nanometres, plus or minus a few, and that that is an objective fact, not a subjective opinion, and therefore the greenness is an objective fact by association.
However, one can counter that with the argument that concepts such as the Electromagnetic Spectrum and our attributing a particular frequency of light to a particular color are also products of the human imagination, and human brain. Such concepts do not exist outside of our minds, and therefore they are subjective interpretations of reality.
One can argue that there is a reality out there, but our description of it, whether in scientific terms of atoms and molecules, or in terms of poetry, drama and art, is all fundamentally subjective.
The wine-tasting experiments I referred to above, also apply to wine connoisseurs but with fewer extreme results. The connoisseurs are less influenced by price than the average person, but still clearly influenced in their opinions as to quality.
Just recently I heard of an interesting experiment designed to test the conformity of expert opinion. A group of experts on a particular subject, sitting around a table, were given a couple of propositions in their field to deliberate upon; call them A and B.
B was cleary correct. A was clearly false and bogus.
After all the experts around the table had studied the two scenarios or propositions, a vote followed, in sequence from one person to the next, as to which proposition was better or more correct.
The way the experiment was arranged was that in reality there was only one true expert sitting at the table. He was the last person to get a vote. All the other participants were just actors. (Mere actors! Didn't have a real job, excepts perhaps in this case serving the interests of science.)
The result was surprising, but also understandable. Each of the actors posing as an expert, one by one, voted A as the best proposition. The last person to vote was the one and only real expert who knew that B was the correct answer.
Would he be able to go against this bogus consensus of opinion that A was the preferred choice, when he knew in his rational mind that B was obviously the superior choice?
No! That was too much to ask. A consensus of opinion amongst 10 or 12 of his peers who were perceived as being experts in the field, was too much to go against. The only true expert sitting around that table, conformed to the majority opinion and voted the same as all the others.
There's a profound message here for the whole of humanity.