At https://en.wikipedia.org/wiki/Special:Log/massmessage there are a number of entries in the form
"Delivery of "X" to User talk:Example was skipped because target has opted-out of message delivery"
When I opted out of message delivery, I expected to be left alone, not to see a notice in my watchlist every time a message delivery was skipped.
An obvious fix would be to replace "User talk:Example" with "Example's talk page" in the notices.