Did your losses come from bad sizing, or were you just picking worse setups with fake money?

Didn't a masonry forum post say to check for missing bricks right before the mortar sets?

My buddy Keith did this exact thing last year, put a 1/2 inch spade bit straight through a cable line running behind a fireplace mantel. The homeowner was more mad about the hole in the wood than the fried internet, but at least he didn't have to deal with a security company.