There are experts who have read everything about certain performance practices, and have developed an opinion on how to play certain kinds of "classical" music, like the Baroque period. The biggest debate among many musicians is how to play certain pieces of music. Most classically trained musicians want to play with the correct style that each piece fits in. There are certain ways to ornament notes, and there are certain ways to articulate notes so it sounds like a piece from the Baroque era. Some musicians may think that you start with the trill with the above note, or start the trill with the lower note. How would one truly know how certain pieces were played? There are no recordings of the pieces from that period of time, and there is no one who lived during that era that is alive. It is really hard to say what is correct or incorrect.
I immediately thought of Glenn Gould while writing this post, who plays many Baroque pieces on the piano. If you lived during the Baroque era, you would typically play any of Bach's pieces on the harpsichord. The thing about the harpsichord, is that you cannot change the volume, because every note is at one dynamic level. One plays expressively with the tempo by speeding up and slowing down to play expressively and in the style that Bach might have played. One may chose to slow down at a cadence to play "expressively." The reason I bring up Glenn Gould is because first of all, he plays Bach's music on the piano, not on the harpsichord. He plays with the volume by playing certain sections louder than others. He also plays the pieces almost like you would from the Romantic era by having these long lush lines on the piano. He plays the trills a certain way, that someone from the Baroque period might not have played. He is one of my favorite pianists to listen to, and there are some that don't like his playing because he does not fit the Baroque style of playing. Is this really that big of a deal to play music a certain way?
I think the main point here that I'm trying to make is to say that there is no wrong or right way to play music. I believe one should play music to the style that is enjoyable to them, and there will always be someone out there that may not like the style that you play, and that's okay. I also believe that a musician who can play in the style that others might enjoy or want as well as playing their own style is a true musician. I believe this because it shows that you truly understand others opinions, and you have also formed your own.