Lawyers: what repetitive/admin task wastes the most time in your practice?

I'm trying to understand how different professional service businesses actually operate. I'm particularly interested in the boring/repetitive work that takes time away from the work you actually want to be doing.

Things like client intake, scheduling, following up with potential clients, collecting information/documents, updating case information, billing, email, etc. — but I don't want to assume what the biggest problems are.

If you could eliminate or drastically reduce one repetitive part of your work, what would it be?

Just trying to understand the workflow and where the biggest frustrations are.