Dev gets told in the morning there's an emergency fix needed due to a critical issue with the app that's in production and that the fix needs to be in the release that will be cut this evening.
Dev drops everything he/she is working on, works frantically all day to get it in 2 minutes before the deadline.
Release gets cut.
Next day release gets trashed because some exec did not like the size of the font used in some obscure part of the app even though it's been this way for 6 months...