[gauku]

I think people are biased towards things that required (or contain some form of) some input from their side.

Robert Cialdini, in his famous book - "Psychology of persuasion", talks about an extreme version of such an effect in the case of Fraternities and Hazing where the members of fraternities display a greater commitment and respect towards their respective fraternity even though they might have had to go through a harsh and humiliating initiation process.

In this sense, IKEA effect, "find" effect, "my kid is the best" effect etc can all be traced to a common ancestor phenomena.