Building a new product can often be challenging, ambiguous work that changes rapidly. Working here takes initiative and drive that some people might not be used to.
The team is not afraid to experiment and iterate on pieces of the product, so if you are used to being in an environment where making mistakes or trying things out is frowned upon, or people are comfortable with the status quo, this may be a bit of a culture shock.
Also if you're used to a very "polite" environment where there is no dissent or challenging of ideas, Root will also be very different (we're nice to each other, but we'll tell it like it is and think challenging ideas makes for far better solutions as we tackle important challenges).