I'm re-reading Sai's intro arc for fic reasons and got momentarily distracted by the sequence of events wherein Yamato gets assigned to Team Kakashi, because it unfolds like this:

Tsunade refuses to cave to the Elders' demand that she keep Naruto cooped up in the village

The Elders agree to this, but only if she allows them (aka Danzo-by-proxy) to choose who will fill Kakashi and Sasuke's spots on the team

Danzo comes in and chooses Sai specifically, but then makes the enormous mistake of giving Tsunade only a general set of recommendations for the last member's qualifications

after which Tsunade turns around and does the absolute funniest thing she could possibly have done:

It's hilariously tempting to think of her doing this as a deliberate fuck-you to Danzo, but it's implied in the text that she doesn't even know about Yamato's Root background - she spends the next few panels explaining to Yamato who and what Danzo/the Foundation are, as if he wouldn't know. (Logically, I recognize that this is probably just because Yamato's Root backstory hadn't been conceived of yet, but in-universe it gives the impression that she doesn't know where he comes from):

It's certainly plausible to read this as her carefully talking around the issue with Yamato - her "surely you've heard of him" could be one of those things where they both know what she means but aren't saying it out loud (due to concerns about surveillance, plausible deniability on her part, etc), so how much she knows is ultimately up for interpretation. I'm not rigidly committed to either read, though, because either way is equally entertaining to me - her picking Yamato as a deliberate fuck-you to Danzo is obviously satisfying, but her NOT doing it as a deliberate fuck-you to Danzo is just as funny, like - we know, canonically, that she picks Yamato because he has Wood Style, and probably also because he worked with Kakashi for so long, but for her to use those completely unrelated criteria and wind up unwittingly selecting the absolute LAST person Danzo would ever have wanted to be Sai's commanding officer is SO hilarious to me.

Either way, I love when Danzo comes into her office to ask if she finished picking the Black Ops commander, and she's like "yeah :) i did :) guess who"

danzo: you better not have chosen somebody like your grandfather tsunade, who chose her grandfather's literal genetic clone: >:)