I'm sorry it's so disruptive that I don't spend the entire time fixated on the board. You see, it helps me to have the textbook open on my lap during class, so that I can read along with the concepts, take notes directly into the book - instead of on scattered pages - try my hand at solving the book's examples as well as the ones you write on the board, and refer to the text when asking a fellow classmate to explain some concept.
I'm sorry it's so disruptive when I confer with a friend during class. You see, I've raised my hand in previous lectures to ask you about something you've said, but your answers tend to repeat, rather than clarify. It's normal for students to speak up during lecture, but they are normally asking for repetition, and so are satisfied without an elucidation. And when I'm reading along to gain a fuller understanding, my confusion is usually regarding a line written in the book, not on the board, or regarding how one should think about a process - neither of which are appropriate to ask you about during lecture, and either of which are necessary to understand in order for me to go on. So I turn to my neighbour, gesture at the board, circle something on the page, let them think for a moment, and then receive a brief written or verbal explanation, the total articulation involved lasting maybe 60 seconds.
I'm sorry it's so disruptive when I, moreso than any of my classmates, speak. I make an effort to be quiet, enough that I am sure the other students talking - and there are always other students talking in this large of a lecture hall - are distinctly louder than I and have longer conversations. In light of this I understand my proximity is probably the disruptive element, as a quiet sound from the second row probably carries better than something noisier from the fourth or fifth row, or way in the back of the 500-person hall. You see, I prefer to sit near the front, where I can easily view the board and hear you, than sit in the back and ignore the lecture.
Altogether, then, I'm sorry it's so disruptive that I must actively participate - take notes, read along, work out examples - in order to learn. You see, I consciously instilled the habit of active participation, because throughout grade school I was easily and frequently distracted during class. As learning was so important to me, I taught myself to distract myself with classwork - read the text, not a novel; scribble notes, not doodles and poetry; figure out examples, not the number of chairs or ceiling tiles. Otherwise I physically could not concentrate in class.
You might, at the point, tell me that if I have such issues, to go see a doctor about a learning disorder. "Well, you should deal with your own problems," you might say, "there is medication you can take."
But you see, I am taking medication. Every morning I swallow a pill meant to alter my brain's functions to fit the requirements of modern educational systems. I take a psychoactive drug known for its high risk of addiction and plethora of potential side effects, of which I have experienced
insomnia, appetite suppression to the point of nausea, drastic weight loss, dry mouth, diuresis, teeth grinding, irritability, anxiety, agitation, loss of interest and pleasure in previously enjoyed activities, dysphoria, and most recently: depression, and suicidal thoughts and behaviour
I wreak havoc on my body and brain so that when I sit down to work on the maths problem set you assigned, I am physically capable of concentrating on my work.
Even then this medication only allows me to concentrate, while my habits, built up over the 16 years until I was diagnosed, are designed to distract. I have to learn how to learn, while already at university, and teach myself the study skills that almost all high school students have picked up to some degree. This means that I had to find, through trial and error, that it is most beneficial in all my classes to have my books open for reference during lecture and take notes in the text.
This also means I will occasionally lapse back into old habits, and spend an entire lecture absorbed in my mobile phone. However, that is neither an unusual way for students to spend your lectures nor does it involve as much talking as when I make myself choose to pay attention.
If, then, my attempts to learn are so disruptive that you must call me out in the middle of lecture, with the textbook you assigned open on my lap and my phone away in my pocket, to have me move away from the classmate I normally talk to, I will cease doing so. I would rather learn than spend an hour staring mindlessly at the board or my phone, but if those are my only options in your lecture, then so be it. I will skip class and study on my own.