Realized the title and final sentence were misleading, was less looking for advice and more looking for war stories. Some of these interactions can feel pretty bizarre from the entrepreneur side and was wondering if anyone else had good ones to share.

War stories are best when you hear both sides. One-sided war stories are mostly like "they made a mistake, and we took advantage of it." But why did they make a mistake? What were they thinking? Did they have bad data, or wrong analysis, or internal disagreement? Were they losing a battle to win the war? That's when it gets interesting.