Drawing on her experience in improvisational comedy, where success depends entirely on ensemble work, Poehler told Harvard's graduating class that collaboration is the key to everything. She listed the improv rules she still lives by: listen, say yes, live in the moment, make sure you play with people who have your back, make big choices early and often. Her career trajectory proved the point — the Upright Citizens Brigade led to Saturday Night Live, which led to Parks and Recreation, each built on the foundation of working with others.