LLMs have finally freed me from the shackles of yak shaving. Some dumb inconsequential tooling thing doesn't work? Agent will take care of it in a background session and I can get back to building things I do care about.
Talking with other knowledgeable humans works just as well for the first thing, but suitable other humans are not as readily available all the time as an LLM, and suitably-chosen LLMs do a pretty good job of engaging whatever part of my brain or personality it is that is stimulated through conversation to think inventively.
For the second thing, LLMs can just answer most of the questions I ask, but I don't trust their answers for reasons that we all know very well, so instead I ask them to point me at technical sources as well, and that often gets me information more quickly than I would have by just starting from a relatively uninformed google search (though Google is getting better at doing the same job, too).