Years before the Broadway hit “Waitress,” Sara Bareilles was an actual server. Juggling pizzas and working at a cafe — plus a stint at a petting zoo — shaped the artist’s work ethic and collaboration skills.

Most recently, Bareilles co-wrote an Oscar-contending song called “Salt Then Sour Then Sweet” for “Come See Me in the Good Light.”

It is a poignant documentary about poet Andrea Gibson, who faces an incurable cancer diagnosis with humour and joy, along with a gut punch.

Bareilles, 46, explains how these first jobs taught her to read a room — on the restaurant floor as well as onstage.

This interview is condensed and edited.

When you were a kid, what did you want to be when you grew up?

A dolphin trainer. It felt like the closest real-life version of living inside “The Little Mermaid.”

What was your first paying job?

At a local petting zoo in Eureka, California, I cleaned up goat poop. I don’t remember working there very long. I also worked at Hot Dog on a Stick and Round Table Pizza.

Do you remember what you earned in high school jobs?

At Hot Dog on a Stick, I think I made around $2.75 an hour, which was more than I made at Round Table Pizza.

What did you spend that early money on?

Music and movies. CDs, cassettes, nights out with friends. I wasn’t saving for anything big.

How did waiting tables shape your writing for the 2015 Broadway musical “Waitress”?

It made the opening number easy to access. I knew the feel of a busy diner — people calling for water, checks, everything at once. Early drafts even had a chorus of customers. Mywaitressings skills absolutely fed the writing.

Why did you like waitressing?

The social part. I loved short, upbeat interactions and the freedom to move. I tried bartending for one shift. I felt stuck behind the counter.

As a waitress, I made great money. I loved my boss. The food was awesome. It was a great job.

Did you keep waiting tables while you started performing?

For longer than I needed to. I liked the structure and community, and I liked cash on hand to hire a band and play shows. I switched to breakfast shifts so I could perform at night.

Are you a good tipper now?

An incredible one. If you can afford to tip well, do it, even if the service isn’t perfect. Life’s too short — share the wealth.

Have any early workplace moments shown up in your songs?

More in mood than specifics. My early song “City” carries the feeling of that time, but I don’t really name the places I worked.

Do you consider yourself a poet?

Not really. Lyrics are related to poetry, but they’re not the same. Poets have a particular lens. I came to poetry later, and I have huge respect for it.

A key theme in the movie is Gibson’s struggle with anxiety. Do you struggle with doubt or stage fright?

Absolutely. Sometimes I feel totally free, other times I’m anxious. As my Buddhist teachers say, the doubting mind is just a state of being. We slip into it without even meaning to. It’s a natural way for the brain to function. And the trick is just letting it be and not getting too attached to the outcome.

What do you get from a live audience?

They close the loop. A song is created, recorded, then shared — and the audience completes it. Every crowd is unique. They’re collaborators, offering energy, vulnerability and a mirror.

Toward the end of their life, Gibson writes up a bucket list. What does your bucket list look like now?

Smaller, intentional moments focused on relationships. After some hard losses these past five years, that’s what makes me feel most alive. Andrea’s list in the film is like that, too.

What advice do you have for an artist starting?

Play live. Bodies in a room can’t be replaced or automated. My manager believed in the 10,000-hour rule — get on stage and stay there. I learned who I was by playing a lot, making mistakes, and keeping at it.

Do you remember your first big paycheck from music?

A publishing check for more than $200,000 showed up at my tiny Santa Monica apartment. I screamed, called my manager, then put it in the bank because I had no idea what to do with it.

What’s your splurge now?

Homes. I’m a homebody and want to love where I live. I’ll also spend on a great meal. I don’t care much about stuff.

How hands-on are you with money?

I have a business manager who’s a dear friend. We do quarterly check-ins. I grew up sort of like lower middle class, so I’m conservative with money. I don’t live beyond my means. Baby girl loves a sale. And give me that hotel soap.

What’s a first-job fact fans might not know?

Round Table’s creamy garlic sauce on the white pizzas is just ranch dressing from the salad bar, and it’s delicious.