This rings very true to me: I like you, so I want you to be right, to the extent that I might suspend thorough analysis of what you're saying. Conversely, if I don't like you, I might ramp up efforts to find out that you're actually wrong.

Look no further than politics for day-to-day demonstrations of this: Does anyone ever apply the same amount of critical rigour to "their guy" as they do to his opponent?