Four songs into her setlist, Billie Eilish pauses. 

"I have two rules for the night," she says, addressing a screaming crowd of teenagers, parents and other adults of all ages at Chase Center in San Francisco on Tuesday. "The No. 1 rule is … don't be an asshole and don't judge anybody in here." The audience cheers in agreement. "And my second rule tonight is you have to have fun." Fans respond with more wild screams, as if proving they're up to the task.

After releasing her second studio album, Happier Than Ever, in July, Eilish is now on a world tour by the same name, with San Francisco being the 26th stop and halfway point. In September, she launched a concert special on Disney Plus called Happier Than Ever: A Love Letter to Los Angeles, an intimate performance of her latest songs. In writing about the special, I noted there's a beauty to hearing her perform live without a crowd to drown her out. 

But now, standing in this massive arena with thousands of cheering fans, I feel something unique for these times: camaraderie and hope. For many of us, this is the first big concert we've been to since the COVID-19 pandemic forced the world to shut down two years ago. We all have to show proof of vaccination to get in, and despite the pandemic still looming, this gives a sense of security, especially with everyone so close together in a packed arena. There's a feeling of much needed unity and optimism, and Eilish appears set on making sure nothing gets in the way of that. 

After she lays the ground rules, I feel myself relax and take her words to heart, as if they've come from a trusted friend. I belt along the lyrics to My Strange Addiction, not worried whether anyone will hear me and judge my out-of-tune voice. This is the largest gathering I've been to in over two years, but it feels as if  the arena suddenly shrinks, and the thousands of people around me and I are all connected by the same desire to have a good time and witness the force that is Eilish on stage. 

At just 20 years old, the LA-based singer-songwriter has garnered a massive following of people lured by not just her ethereal voice and music, but also her bold, unfiltered personality. Earlier in the evening, Eilish tells the audience, "It kinda stinks in here. Does it kinda smell, like, musty?" She laughs, as if joking with her pals. Around 20 minutes later, as she's getting ready to play her next song, she pauses and says she just realized something. 

"I fucking forgot to brush my teeth," she laughs. "I have bad breath right now, and I want to literally scream."

Being at any large gathering after years in isolation would feel amazing, but there's something about Eilish and her candor that makes this an even more exceptional experience. Skipping out on elaborate costume changes and intricate dance routines, she wears an oversized black and white T-shirt and matching shorts throughout the night, jumping as she belts out her songs while encouraging others to do the same. On stage, it's just her, her brother Finneas on guitar and keyboard, and Andrew Marshall on drums.

Eilish's evocative voice and heart-wrenching lyrics are what made me fall in love with her over three years ago. And given how tumultuous the last two years have been, her music -- familiar, moving and reassuring -- has served as a much needed refuge. 

But it's her honesty with fans about her own struggles that took my love for her to the next level. Eilish has opened up about grappling with anxiety, body dysmorphia and self-harm, allowing people dealing with the same issues to feel a little less alone. In her song idontwannabeyouanymore, she sings, "Tell the mirror what you know she's heard before, 'I don't wanna be you anymore.'" Knowing her battles with self esteem and mental health, it makes it all the more meaningful when she tells the crowd to be grateful we're all here and alive. 

Another song she performs, Your Power, is about people who abuse their power, particularly men who take advantage of young women. In one part, she sings, "Does it keep you in control? For you to keep her in a cage?" After finishing the song, she reminds the crowd that everyone has power, and that it's important not to abuse it. She admits even she needs to remember this sometimes. 

Eilish has also addressed the challenges of fame and dealing with public perception, posing the question in her song Everything I Wanted, "If they knew what they said would go straight to my head, what would they say instead?" 

But tonight, it all fades into the background. Early in the show, Eilish tells the audience, "Don't think about anything bad. Take all the bad thoughts and go like this." She places her hand to her head and mimics pulling said thoughts from her mind, then letting them go. "I want us all to just not worry about being looked at or judged or whatever. I want us to just feel free and good, no matter how old we are, how young we are, where we are in here. It doesn't matter, we are all equal."

Amid all the screams and cheers, I feel the tension in my body disappear, and I let go of any thoughts about the past or future and focus on how lucky I am to be here right now. There's comfort in hearing these words from someone who knows, more than just about anyone, how heavily the world and people's opinions can weigh on you.

But that's not something to worry about here. Eilish has created an oasis where anxieties and fears melt away, making room for us all to fully enjoy the present moment.  

"You can put yourself in a mindset to not have a good time, [or] you can put yourself in a mindset to have a good time," she says. "So let's have a good time."