“This is the best cake I have ever eaten,” my daughter declared. She had spent the entire morning baking and was reveling in the fruits of her labor, savoring every bite. The cake certainly tasted good, but to her, it was the most delicious cake in the history of the world. Why? The answer is as simple as pie: Because she made it.

Labor often leads to love — the more effort we put into something, the more we value it. A few years ago, Duke University’s Dan Ariely and two colleagues explored the psychology behind the phenomenon. In one experiment, they asked participants to assemble an IKEA storage box. Others were given fully assembled boxes. Both groups were then asked what they would pay for the boxes. The builders were willing to pay far more (63% more!) than the non-builders and far preferred their boxes to the pre-assembled ones.

The researchers call this the “IKEA effect” in honor of the Swedish manufacturer whose products typically require some assembly. The theory is that the builders assigned greater value to the boxes they built because successfully completing what they set out to do made them feel competent, capable and proud.

I can relate—to me, the needlepoint pillows I have made are far more beautiful and valuable than anything store-bought.