Could you, please, clarify the differences between the following sentences and point out the most acceptable options? :?:
1. I have a house ON the beach. and I have a house AT the beach.
2. My house is always full OF friends. and My house is always full WITH friends.
3. I'm a nurse. If I have work AT the hospital, I get up early. and If I have work IN the hospital, I get up early.