Do readers prefer most things to be explained in a story by a dialogue between characters?

It's a school of art, a form of realism.

In the real world nobody ever tells you what people are thinking. Telling the reader what the characters feel is a fictional view of life.

It depends on what exactly is being explained.

Settings:

no. I'd rather read about the place's description. Plus, that would be a weird conversation.

Other characters (gossip):

It's okay. I mean, it sets a little bias on your opinion of the discussed character, and can always be misleading. It's just as easy to describe without dialogue. I have no preference

Their own personalities:

I LOVE reading how characters react/respond to different things and drawing my own conclusions. For example, i'd rather read:

"You are so pathetic! You're ugly, stupid, and smell like goat farts," Sally yelled at stephanie.

Stephanie curled inward, afraid of Sally's rage, "Please, you can have my lunch money." she stammered.

than:

Sally was the school bully.

Obviously, I do enjoy some details of how characters react (see above), but in general i like dialogue more in that scenario.

I think the key is to find balance. You don't need someone explaining every detail in the room because who does that? I love this post by the Novel Doctor that relates to this showing how to use dialogue to explain things without over explaining:

“Is the sword shaped like a cross with a sharp dagger end that’s dangling over your head making you nervous, Edward?”

“No, Jacob. But you should be scared because I’m baring my fangs right now and they’re really menacing because they’re sharp and I’m smiling at the same time which is ironic and therefore underscores my obvious lack of fear.”

Please. Don’t. Go. There.

Instead, establish the scene so we know Edward is standing under the cross with the sharp dagger end. Then all you have to write is this:

“Nervous?”

Edward looks up at the cross then back to Jacob. He smiles, then bares his fangs.

“Not even a little.”

This just makes me laugh but it does really help.