You will annoy, and yet

"He is a good creature, and more sensible than any one would imagine," said Dorothea, inconsiderately.
"You mean that he appears silly."
"No, no," said Dorothea, recollecting herself, and laying her hand on her sister's a moment, "but he does not talk equally well on all subjects."
"I should think none but disagreeable people do," said Celia, in her usual purring way. "They must be very dreadful to live with. Only think! at breakfast, and always."*

Summary of Celia's contribution: Disagreeable people are those that talk equally well on all subjects. and such people are dreadful to live with, especially at breakfast, and always.

Drilling down: To talk equally well on all subjects means--is knowledgeable, very, and/or speaks convincingly as if s/he is knowledgeable, albeit annoying virtually (as in "in truth") always.

For who would communicate "what they know": You will annoy.

Guide to map (biased): Ask questions. Pronounce sparingly, and only if asked overtly or tacitly.

Alternatively, Do the homework and pounce; start or finish the fray.

On the other hand, Dorothea: Regardless of appearances and limits in knowledge and ways of expression, her beau is a good person. You have to know him [the person]. 

Guide to revised map (also biased): A little understanding, a little patience, a little license, a little forgiveness, a little live-and-let-live, a little . . . what should we call it?

Meta guide to maps: Withdraw or engage. To withdraw is clear. But engage? how?  (Why is another question.)

Engage with the best that you know--and as most openly and effectively as you can till words end, even if not all yours are those agreed upon as sufficient to proceed.

Thus it is clichés all the way up and down beginning with: Choose your frays.

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* _Middlemarch, A Study of Provincial Life_, George Eliot.
** One answer appears previously and rationalizes this blog.