Cordelia was barely even a character by the time of season 4. Even before then, she was basically being written as a pod person and Angel cheerleader in late season 3. At least Jasmine was an explanation for season 4, I still don't know what was up with the whole turning her into an angel/higher being who can ~cleanse~ Conner of his hatred, not to mention parroting, "Angel is the only person I care about".

And badly written ones are worse I'd say! I can enjoy a villain most of the time, it gets annoying usually only when the writing attempts to whitewash them and refuses to recognise that they are an actualfax terrible person