Do you ever work for hours on some recalcitrant computer/networking device, doing everything humanly possible to make it work but instead spin your wheels so much they'd think you're at the drag races?
So in disgust, you finally leave (or throw) the piece of sh** device or just take it elsewhere to plug it in, then bada bing, it magically starts working without error?

Case in point:
Called today for an onsite on a client's wireless router (stable for over one year) which is now acting all kinds of screwy. Check the adapter voltage (good), check the external lights (only good for 20 seconds before the power light turns from green to a blinky green or a kinda yellow. The device is not responding to what I thought was the IP, Doesn't respond back on a MAC request either. Okay, reset my notebook a few times with different IP addresses for the ARP/IP subnet scanning. Reset the device a couple times with reset button. Check the item's heat by hand, plug it into a UPS, blah..blah...blah...

Inform the client the hardware is defective.

Take the item on a power off 40 minute trip to my office for further dissecting, and wouldn't you know it, bada bing it immediately starts working right on first power up and is still working 60 minutes later.

But I bet if I take it back, it'll start acting up. Maybe it's just tired of its surroundings?