Or
B) Get impatient, cut them off and tell them everything you know about the topic?
Or
C) Patiently let them finish, THEN tell them you already know, and everything you know about the topic?
I personally have a tendency to be an impatient douche sometimes so I admit I don’t always handle these situations with the greatest patience & social grace.
D) Excitedly finish their sentence to create a moment of shared understanding
“So you have xyz and then–”
“Oh yeah! B! It’s so cool, isn’t it? And then C and D!”
“Yeah!”
Fist bump
Or at least this is what I would want to happen if I ever actually talked to people. >.>