What is the last client complaint you got that you wish you had heard sooner?

Most complaints I get are not new. They are old, quiet, and only turn into a complaint once someone finally runs out of patience. By the time I hear it, the person has usually been annoyed for weeks and just never said anything, or said something small that I did not register as a warning. Curious whether that pattern is just me, or whether the actual complaint almost always arrives later than the moment the person first felt it.