Five @Stata commands or features you can't live without. Hopefully we'll all learn something new and useful. I'll start—
1. mata
2. margins
3. glm
4. twoway
5. contract
(in no particular order)

So far I've learned about…

-lookfor
-char
-isid
-browse (I'd open data editor )
-a few others

Also a tip of the to R users who've been—for the most part—well behaved and, when trolling, did so (I think) good-naturedly.

Hopefully others have learned new things too.