Oh PCB layout. How you spite thee.
What's a 'coaster' you ask? A coaster is something that sits under a coffee mug (or beer glass) and prevents the vessel on the coaster from leaving a visible ring on a table. It's also a name for a completely screwed up PCB.

This is a panelized PCB design. 'Nordic-FOB' is a design that I've been working on and is ready for production. The board has an ATtiny combined with a Nordic nRF24L01 radio, all housed inside a Polycase keyfob enclosure. The 20mm coin cell battery runs the system for a couple years. You hit a button and the Nordic radio chirps the wireless information over 2.4GHz - kind of like the keyfob for remote entry of cars. Sounds cool, if it worked. What's wrong you ask?

That is wrong. What's that?

That is a tiny, tiny disconnect from one of the pins on the nRF24L01 to ground. See that little line? That's an airwire indicating there is not yet a connection. There should have been, because the ground pour should have poured onto that pad. But Eagle failed me. I failed myself. Because of this tiny (and I mean 0.005" tiny) disconnect, the board is completely worthless. I've been laying out PCBs for years, and I still produce coasters.

Life after airwires.