The only scenes that made the movie worthy of the rated R stamp seemed to be shoehorned in and ridiculous. The first is a scene near the beginning where Matt Damon is attending a very PG-13 party, where he takes some drugs and the movie takes you into a kaleidascope, and in the final scene of this colorful adventure, there is a short glimpse of a toplees woman in a pool. Tits out of nowhere for no reason. The second is some surprise vulgar language towards the end. While there was some F-bombs in the earlier portions in the movie, this was on a different level.
On another note, the human trafficking implications of downsizing would be massive. People would collect small people and dress them up like characters and pit them against each other like cockfighting. Rich children would have small human beings as pets. There are so many other horrible implications. There are also some kinky and practical ones as well. Use your imagination.