a good thing - A good thing is someone who means the world to you. They’re

A good thing is someone who means the world to you. They’re like your best friend, your lover, and your life insurance.

My girlfriend is a good thing. She puts up with my dumb jokes.

My brother is a good thing. He always lends me money when I need it.

My dog is a good thing. He never judges me when I eat out of the trash.