In general, I feel that it is usually good for us to figure out in clear terms what it is that we want, and for us to be brave enough to ask for it. But, one thing that I think helps with clear communication is to be conscious of the on the fact that boundaries are not always bilateral or reciprocal.
That is to say, I think that “Heyyyy! You just asked me to not do x, and now you’re doing that exact same thing!” is usually an unproductive thing to say. If you ask me to close my mouth when I am chewing, I realize that you are not necessarily agreeing to also close your mouth when you chew – unless I specifically ask you to do so also, and you agree.
It seems to me that some people’s childhoods have left them with specific sensitivities such that common, inoffensive behaviors may really bother and set them off, although those same behaviors are neutral for most other people. I think part of being a friend is being willing to take such sensitivities into account, as long as they are reasonable and respectful, even if they are unusual.
I also have seen situations where one person of two has more of a problem with a behavior than another. If person A has a frequent habit of interrupting people, and person B asks them to please be mindful of interrupting less, than I feel that that should not set up a “gotcha” for person A to spring on person B if person B interrupts once in a blue moon. The situation is not equal for the two of them. Person B may of course frequently do something else that is different but also difficult or offensive, and perhaps it is appropriate for them to be responsible to person A for that instead.
“Don’t do unto others as you would have them to do unto you; their tastes may be different.” — George Bernard Shaw