Temping taught me a ton ... mainly about what I didn't want to do with my life, but still, that's invaluable!
In seriousness, though: temping was great for me - rounded out some of my office skills in some cases, or bored me out of my wits in others but never for so long I couldn't stand it. My jobs included: printing out physical copies from microfiche by the thousands for archival purposes, stuffing corporate mailboxes in the basement of a Fortune 500 headquarters while listening to elevator music, data entry and so forth. Some of it provided resume material, other parts didn't, but at least it showed I was continuously employed to the extent that I 'worked for' (or through) the agency for a while.
Paid decently, I have to say, and in the really terrible jobs I got a lot of sympathy/help from the full-timers, who encouraged me to take breaks, ask for assistance if needed, and drink as much coffee as I wanted to stay awake and sane
In my case, it meant I didn't get stuck in one ultra-boring job - I at least got to spread it around. And I happened to get paid a bit more than I would have as an entry-level worker in the same positions. And it also meant my 'job' was in less danger, since they really were just bouncing me from one gig to the next. I didn't always have predictable hours from one month to the next, which was the drawback, but *shrug*
"In the absence of clarity, diversification is the only logical strategy" -= Larry Swedroe