Do you believe in ghosts/spirits?

So I've been staying at my mom's house while in the process of moving, and as kids we always said her house was haunted because super weird things would happen (voices in the middle of the night, footsteps, piano playing itself etc) and I'd forgotten about it until just now I got up to get a glass of water and when I laid back down, the doorknob to my bedroom turned itself (heard it squeak as it turned slowly) and opened all the way, ever so slowly. I looked up expecting my mom to walk in but nobody was there. Now, I'm a grown adult, lying here, scared as hell staring at this door lol. Anybody else believe in this stuff? Have stories of your own?