- I'd be curious if the origin is really the Navy seals. I couldn't find in my brief searching any where else...
- I like John Wooden's saying "be quick but don't hurry". I mentioned that to a doctor who trained in the mid 20th century and he said that surgeons had a line "hurry, but don't rush"
- several people here mention that they learned this phrase in the military
- the first written mention I could find is in a 1998 army report [0]
- the first Google Books hit for this phrase is from 1970 but this seems to be an error - the full text preview is from a different, recent book [1]
- Internet Archive has a lot of hits - but the earliest ones - except for the army report mentioned above - are from the 2000s (don't be fooled by wrong publishing dates in the metadata) [2]
- Google Ngram Viewer shows a brief appearance around 1980 (maybe a fluke) and then a steady rise in the 2000s [3].
- In one army magazine I saw an extended version: "slow is smooth, smooth is fast, fast is deadly" (which doesn't transfer that well to other professions)
- I like John Wooden's saying "be quick but don't hurry". I mentioned that to a doctor who trained in the mid 20th century and he said that surgeons had a line "hurry, but don't rush"