A list of four word prompts I found on Tumblr, so credit respectively, I may turn some of these into one-shots considering I get the time :P
"Please come with me."
"You're always number one."
"I can't do this."
"I won't let you."
"Maybe I'm just crazy."
"I'm not even sorry."
"Honestly, just stop it."
"I believe in you."
"Don't be a bitch."
"Who were you with?"
"Please talk to me."
"I can't trust you."
"Don't be fucking rude."
"Is that my shirt?"
"So, it was you."
"I need to go."
"Hey, I said stop!"
"D'you wanna go out?"
"You always this quiet?"
"I don't want you."
"This was never right."
"I'm out of here."
"Just stay with me."
"You can trust me."
"Alright, I love you."
"I'm sorry, but no."
"Will you help me?"
"You're a terrible cook."
"Can you shut up?!"
"You love me, right?"
"I really need you."
"I don't love you."
"I'm not doing this."
"You don't want me."
"Let me help you."
"You're such a bitch."
"You think you're funny?!"
"Will you marry me?"
"Are you fucking insane?"
"Sorry, were you sleeping?"
"You look really tired."
"You need to go."
Pick one :D