Oh god, so much (life long public sector corporate worker here with more than a lifetime's worth of pointless busy work). Copying and pasting data from one database into a word form (or exciting new development, an MS online form!) so it can be entered into another database by a different team (far too much to ask that the databases talk to one another!). Filling in many many forms to access help or support or data from other corporate teams or 'partner' organisations asking for my name, email address, job title etc (when I am about to email them the form, my signature contains my name, job title, phone number, could you not read it from there? Or take it from one of the other hundreds of similar forms I've sent you previously?).
Arguing with people about whether they hold data I need (they do) and whether I'm entitled to see it (I am), in order to complete some of the said pointless transference tasks.
The many, many meetings at which my opinion/input is neither needed nor wanted but I have to turn up to be polite. Similarly hosting meetings of people whose opinions I don't need or want but who would be offended not to be asked.
Writing reports and papers I know are destined for the bin without being read by anyone other than maybe my immediate team who know the full content already.
Summarizing long reports or complex issues which my boss hasn't got time to read/understand into elegant precises or executive summaries - to be told he 'needs to see the granularity to understand the exam question' (or similar blurghy corporate bullspeak). So, send him the data, tables, details etc for him to say 'too much information, need the headlines only/just tell me what's the so- what here' and repeat, endlessly...