The software world
One-way door
An action you can't easily undo. Editing a file is a two-way door — roll it back. Sending an email, force-pushing a branch someone already pulled, dropping a database table, spending money: those close behind you.
Why it matters
Part of Deciding what to approve → It's the sharper of the two risk questions, and it stacks with blast radius rather than duplicating it: blast radius asks how much could be affected, one-way-ness asks whether you can get it back. One question catches most of the disaster stories — if this turns out to be wrong, can I take it back? Yes: approve and move on. No: read it again first. (The phrase is Jeff Bezos's, from a memo about decision-making.)
see also