Do something stupid.

Not at Envoy, but I've seen people fired after OE following numerous F/O complaints, and I've seen people fired for doing anything from smearing their hotel room with feces to threatening crewmembers, drinking on the job, lying, screaming at hotel check-in staff. Line checks, unsafe behavior, damaging an airplane, even social media posts.

I've also seen an upgrade fail his LOFT ride after his upgrade training is all but done; there's no such thing as "non-jeopardy," no matter what anyone may tell you.