Those signs are the work of street artist Scott Froschauer.
The Glendale Library, Arts and Culture Department launched Froschauer's "Word on the Street" art installation last week, placing 20 of Froschauer's signs at parks throughout the city.
Froschauer said the street signs we see every day are mundane and deliver a negative message. So, his street signs are positive, with messages such as "grow" and "do your best."
The signs will be on display for one year, and if you'd like to see them, Froschauer has a map showing the 20 locations of his signs on his website.