A good personal motto. Always being in trouble, constantly doing things that do not measure up to expectations, literal translation - "always in the shit".
Dave's D.I.Y. plumbing effort caused a flood in the bathroom which ruined an entire floor and brought down the ceilings in the lower floor.
"Dave, everything you do goes wrong. As they used to say in ancient Rome, "semper in excreta". You're always in the shit. This time, literally!"