Seems logical. They made the call in the first place.

I always call back.

They called for a reason, so if the conversation isn't over, they should call back and continue. If the "callee" is busy, the conversation continues another time.

The one who dialed the number, since they can easily hit redial.

Had to pick one but I think it really depends on the actual call itself

I might, or not.

I picked ‘the caller’ but it actually depends on the situation. If the call dropped due to a bad connection on my end, I will call back when I have a better connection.

If the callee had wanted to talk to me, they would have made the original call.

You initially made the call. It's your responsibility if you want to continue the conversation.