The worst abusers are the ones that mix vital emails with marketing and fluff. In the US you have to deal with the Social Security Administration your entire adult life. You need to deal with them while paying into the program during the working years and also while cashing out in retirement. So you can't just ignore communications with them, but yet most emails are fluff like holiday greetings, reminders not to be scammed (which are repeats of the same advice they gave in all previous emails).

Banks also do this, but they at least use the same subject lines that I can auto-filter.