Because you like Ethel Mertz in I Love Lucy

Scooby-Doo always keeps his priorities in order: eat snacks first, solve mysteries later. See them in Scooby-Doo.

Benoit Blanc is Sherlock with Southern charm, and a mysterious benefactor. See them in Knives Out.

Selfishly taking her father’s place to fight in the Imperial Army, Hua Mulan risks treason if they find out she isn’t who she says she is. See them in Mulan.

Rory Williams is a caring companion whose specialty is looking after others. See them in Doctor Who.

Most kids hope for a car for their 16th birthday, but Mia Thermopolis' present is a country to rule. See them in The Princess Diaries.

Whether it's a companion he’s failed or lingering guilt from the war, the Doctor can never truly let go of his past lives. See them in Doctor Who.

The Genie is the perfect buddy, granting every wish we might have and keeping life good-spirited. See them in Aladdin.

A self-proclaimed diva, Mercedes Jones is on the hunt for a stage worthy of her talents. See them in Glee.

Sam Weir lives for the simple things in life: watching Saturday Night Live and reading comic books. See them in Freaks and Geeks.

Everything is handed to Sarah Cameron on a silver platter. The problem is that she doesn't want any of it. See them in Outer Banks.

Khan Noonien Singh is super strong, super smart, and out for revenge. He always seems to be two steps ahead of his enemies. See them in Star Trek Into Darkness.

A compassionate medical student, Martha Jones has found a Doctor she can really look up to. See them in Doctor Who.