"How long will this bug that you have no background or context for take to fix" I DON'T KNOW

Three words we should say more often

Okay okay, you don't know.... but how long do you _think_ it will take? come on we need an answer now so we can tell the client it will definetely done by then and yell at you when you don't have it fixed yet
- every project manager

To stem the tide of panicked "when?"s, always follow "I don't know" with "let me get back to you on that. [x] is still your email, right?"

PM translation: By the end of the remaining business day.