The IKEA effect is the tendency to place disproportionately high value on objects that you have partially assembled or created yourself — regardless of objective quality.

The Research

Michael Norton, Daniel Mochon, and Dan Ariely found that participants who built IKEA furniture themselves valued it about five times higher than participants who evaluated identical pre-assembled items. Importantly, they valued their own work as much as experts' work.

Why Labor Increases Perceived Value

• Effort justification — the work invested must mean the object is worth it
• Ownership enhancement — creation triggers ownership feelings rapidly
• Competence signaling — completing the task signals capability, which attaches to the product

Where This Shows Up

• Entrepreneurship: Founders dramatically overvalue their products relative to market reality
• Cooking: Meals you cook yourself taste better than equivalent meals you didn't prepare
• Customization: NikeID shoes feel more valuable to buyers despite identical materials
• Startups and VCs: A founder's valuation of their own company is almost always inflated

Reference:

Wikipedia: IKEA Effect

https://en.wikipedia.org/wiki/IKEA_effect