Mary Kate and Ashley Olsen
Ashley Olsen (right) has called her twin Mary-Kate Olsen (left) her best friend. Above, the sisters accept the Womenswear Designer of the Year Award onstage at the CFDA Fashion Awards on June 1, 2015, in New York City. Getty

In between Mother’s Day and Father’s Day (and let’s not forget National Donut Day) comes a celebration where we can pay homage to our friends, our best friends to be exact. Monday, June 8, is 2015's National Best Friends Day, and in honor of the little-known and unofficial holiday, let’s celebrate with 10 quotes about close pals. Whether your consider your cell phone, your sister, your mom or your dog your best friend, we've got the perfect quote for you!

Unless noted, the following quotes were obtained from BrainyQuote.com and QuoteGarden.com.

For those who consider their technological devices to be close friends:

“My cell phone is my best friend. It’s my lifeline to the outside world.” -- Carrie Underwood, Esquire (2009).

When your siblings are your closest pals:

“She’s always there for me when I need her; She’s my best friend; she’s just my everything." -- Ashley Olsen on her twin sister, Mary-Kate Olsen, TV.com.

For those who consider their significant other to be their best friend:

“I’d be nothing without my wife. She’s the coolest. She’s the greatest. She is the smartest. She’s the funniest. I love her so much. She’s like the – it’s like your best friend for the rest of your life." -- Jimmy Fallon.

“Your kids are happy if you’re happy. And if your love is happy, then everything works. I think a lot of people think once the children are there, it’s all about the children. But you can’t forget about your best friends, you lover, your husband." -- Heidi Klum.

For the select few who call their material possessions friends:

“Maxi dresses are also my best friend. They take me from my morning coffee to the beach, to nighttime." -- Hilary Rhoda, Harper Bazaar (2012).

For those who consider music to be more than a pastime:

“Music has been my everything since day one. It’s been my shoulder to cry on, my rock and my best friend," -- Christina Perri.

For those with long-standing friendships:

"Best friends don’t necessarily have to talk every day. They don’t even need to talk for weeks. But when they do, it’s like they never stopped talking." Author unknown.

For those who consider their mom to be their best friend:

“A mother is the truest friend we have, when trials heavy and sudden fall upon us; when adversity takes the place of prosperity; when friends desert us; when trouble thickens around us, still will she cling to us, and endeavor by her kind precepts and counsels to dissipate the clouds of darkness, and cause peace to return to our hearts.” ― Washington Irving, Good Reads.

And, of course, for those with best friends that walk on four legs:

"I talk to him when I'm lonesome like; and I'm sure he understands. When he looks at me so attentively, and gently licks my hands; then he rubs his nose on my tailored clothes, but I never say naught thereat. For the good Lord knows I can buy more clothes, but never a friend like that." -- W. Dayton Wedgefarth

Finally, this "Saturday Night Live" alum says what we are all thinking:

"I still want Oprah to play my best friend. I want to spend time with Oprah. And I don't know what I need to do to make that happen." Tina Fey, Gothamist (2008).