Human languages are a mess. Some mix left-to-right and right-to-left. Some have variable amount of diacritics. Some have non-well-defined character sets where just trying to map it to a manageable complexity still loses cultural heritage. When you are fondly remembering the good old times of ASCII, you just wish back to be able to ignore anyone not speaking English. (Which is in your right to do, if you so desire.)

Unicode was mostly OK when it wanted to encode multi languages. It started to get a mess when thought it needed to do more.