I would not call these last ones dream jobs. More like dream-crushing jobs...
My work in facial recognition is partially because I can do the work at all, few can, and I also do this work to know what it is, it's capabilities and limits, so I'm not in the dark and can influence it's use. I'm an ethical person, and I voice my ethical concerns constantly, insuring the systems cannot be easily abused.
Those “three letter agencies” may offer resources and projects that one would struggle to find elsewhere.
To some people, being a Marine is a dream job. To others, that lifestyle would be soul-crushing.
I suspect that jobs in a TLA are closer to the Laundry files than James Bond.