Life is a lot like improvisational comedy, said writer, actress and Saturday Night Live star Tina Fey last Thursday afternoon, as Greenwich Academy bid fond farewell to its 179th graduating class.

Sharing several tips she learned while studying with Chicago’s famed Second City comedy troupe, Ms. Fey told students to be creative, work together and learn from failure — keys to negotiating a tricky scene, as well as making it in the real world.

“There are no mistakes, only happy accidents,” Ms. Fey said. “The most unusual ideas are usually the result of happy accidents. Just look at Viagra, or the Reese’s peanut butter cup.”

Ms. Fey’s remark drew big laughs from the crowd, which sat under a giant tent on the GA lawn. On stage, the graduates, decked out in traditional white gowns, listened intently as their top choice for commencement speaker expounded on the educational benefits of coming up short.

“There’s something about flopping miserably that can almost make you giddy,” Ms. Fey said. “Once your worst failure has been realized, you’ll realize you’re not dead.”

Failure, at least thus far, might be something of a foreign concept to the GA girls. As Head of School Molly King recounted, the class of 2006 excelled at athletics, academics and the arts. The varsity squash team, for example, recently won its 10th straight New England title, and its competitors at the tournament voted the squad most sportsmanlike.

“You’ve displayed excellence in every arena,” Ms. King told the 72 graduates. “But you’ve never lost sight of the importance of being good, being fair and showing grace under pressure.”

These qualities, Ms. Fey later said, could one day help one of the girls become the first female president.

“If Condi and Hillary blow it, it could be one of you,” she said.

Rather than look too far ahead, though, many students took Thursday’s commencement as a chance to reflect.

“It’s all the little moments we’ve shared that have permanently joined us together,” said elected senior class speaker Olivia Frazao, stringing together a list of memories that included singing Abba songs on school bus trips and hanging out with the Brunswick boys near the campus vending machine.

“We’ll carry this world with us wherever we go,” she said. “We carry each other inside of us. We’re sealed inside of each other’s histories, and our histories can never be taken from us.”

Earlier in the ceremony, the students recognized retiring Head of Upper School Sharon L. Dietzel, making her an honorary member of the class. Ms. King then presented the Katherine Hewitt Award — recognizing the girl who has “derived and has given the greatest pleasure to her associates in her work with them,” as voted by the entire class — to Elizabeth Zimmerman.

For Zeena Audi, a GA student for 13 years, the day was nothing short of surreal.

“It’s just a weird feeling — I remember being a flower girl,” she said, explaining that when she was younger, she used to participate in the graduation ceremony, performing the traditional duty of walking on stage with a basket of flowers.

“You come to all the graduations, and you see all the girls in the white dresses,” added Hanna Snyder, who attended GA for the last four years. “It feels weird to now be one of those people.”

“It almost makes you want to cry,” Hanna added.

School President Chase Kreuter was similarly sad to leave the school she’s long called home, though she said she was looking forward to the fall, when she’ll head off to Kenyon College in Ohio.

“I’m so excited — it’s so great to be here,” she said, singling out this year’s lacrosse season as what she’ll remember most about her days at GA. “I can’t believe it’s over. It’s gone so fast.”

Very much aware of the speed at which life passes, Ms. Fey told the students to cherish each second of the graduation.

“Feel your feelings now, because 10 years from now, you won’t remember a second of this,” she joked.

Turning to the parents in the audience, Ms. Fey said it was important to let kids go off and explore the world. She said her long road to success led through a crumby neighborhood in Chicago, where she would routinely witness police busts while waiting to catch the subway.

“These beautiful young women you have protected and nurtured and raised so carefully for 18 years are going to leave home and move to big cities all over the country and live in terrible apartments in transitional neighborhoods,” she said. “And you have to let them.”

Taking about sexism in the workplace, Ms. Fey, who wrote the script for the film Mean Girls, said women shouldn’t get caught up in cattiness or feel they have to be the only female in the office to get what’s rightfully theirs.

“This is a myth that permeates our society — the myth there won’t be enough,” she said to the graduates. “You guys already know better than that. If we’re good to each other and take care of each other, you’ll always have enough.”

Ultimately, Ms. Fey urged the girls to go out and pursue their passions, whatever they might be.

“Be psyched about the future that lies ahead of you,” she advised. “The future that lies ahead of you is boundless.”

“Also, always wear a bra to work,” she said.