Contradictory facts about the hated party are unconsciously discarded before reaching conscious analysis.
A genuinely sound proposal is dismissed the moment its source is identified as the enemy.
Real achievements by the hated party go unacknowledged, distorting your competitive picture.
Before reacting to any idea, proposal, or piece of feedback — strip its source. Evaluate the content in isolation. Then ask: would I accept this if it came from someone I admire? If yes, your hatred is doing the analysis, not your mind.