When you know someone is exaggerating about their tech knowledge.

I rely on reviews of products to filter out which products not to buy.  On Newegg, every reviewer is required to provide self-determined rating of technical knowledge.  As you might expect, most people overrate themselves.  Here's some examples of people who rated themselves 5 out of 5 stars:

Ryan writes, "Hard drive didn't work out of the box. Plugged it in and Windows didn't recognize it. Turns out my PC also won't boot with this plugged in to the USB port."
 -- Yes Ryan, because you have USB set up as higher priority at boot.  (It's how one can boot ChromeOS from a thumb drive.)  And, it's not that Windows didn't recognize the drive, but that you haven't mapped it; plug and play has its limits.

 Joseph writes, "I have a brand new system works flawlessly I plug in this drive and try to copy it is my system core dumps with a Watchdog_Clock Error every single time."-- It's not the peripheral, Joe, it's your motherboard's BIOS and flaws in how it tackles data flow.  You're going to run into this issue even if you buy a different peripheral drive.

James writes, "First call to tech support ended up with downloading a new firmware version and being told the software would 'find' my device on the network. Not what I read, but ok we'll see. Tech was wrong, the device has a RANDOM SUBNET ASSIGNED. You will take years to try to get your PC to find the device."-- Well James, unless you attached directly to your NAS and changed it, you would always expect it to assign itself a random subnet IP address when attached to a router. 

I realize that computers shouldn't be this hard.  But, if you're not a certified computer nerd who hand-codes, runs an open WRT router and builds computers from the ground up, why rate yourself 5 stars?  Just because you play RPG, love tech and your parents rely on your knowledge, doesn't make you an expert.

Funny thing is, many demonstrably knowledgeable reviewers rate themselves 4 out of 5 stars.

FWIW, I rank myself 3 stars.  My strength isn't my knowledge of tech, but my ability to find answers.