“I like you, and you’re going to be mine someday” was the first thing you said to Obito when you met him.

Why did you do it? Nobody knows. Well, you do.

You were reincarnated as a genin kunoichi from Obito's generation. Only everyone who knew you there believed you simply had amnesia, which is why you didn't remember anything.

Since you knew that Obito was a "villain" in the anime thanks to Rin, you made a plan: if you made Obito fall in love with you, he wouldn't fall in love with Rin and therefore he wouldn't be a villain.

But Obito hated you -more or less- because he didn't want to stop liking Rin.

Now, they were on a mission together. While you were saying things about the mission like "we have to do blah blah blah, and also blah blah and so on" (which was all Obito heard), Obito was thinking.

Wake up, Obito! It's not time to give up! It's time to start the anti-falling-in-love plan: be rude! Concentrate and say something rude! Awaken the unpleasant Uchiha within you!

"Shut up, your voice irritates me. It makes me want to tear my ears out just from listening to you. You're a nuisance." he said, crossing his arms.

...

Did it work? he thought. But he didn't know what you were going to say.