Eren: 

 You love Eren with all of your heart, but when it comes to one of his little Titan speeches, it can get tiring. You admire his passion and commitment, but it just seems consistent. He'll go on and on about how he'll kill every one of the Titans. You understand why Eren feels this way, but you're just worried for him.

Levi:

 Levi's not the person to get on your nerves, but when he does you prefer not to tell him. The only frustrating thing about him is that he tends to ball up his emotions (other than when he's fighting Titans) and pretend like he's okay. You try to ask him what's wrong, and he'll never respond or act like nothing's wrong.

Armin:

  Let's face it, Armin doesn't actually do anything that annoys you. If he ever catches himself stressing you, he'll instantly apologize over and over again until he feels like he's apologized enough.

Erwin:

   Erwin tries his best to be on your good side, but even he can't help himself sometimes. Erwin has the tendency to stay locked up in his room for long periods of time, surrounding himself with stacks of paperwork. However, once he does do this, he'll quickly realize what he's done and apologize to you. 

Marco: 

  Marco can sometimes obsess over the Military Police, and how he can't wait to join it. The only reason you find this annoying is because you wanted to join the Military Police, but you didn't make the top ten. You try your best not to be annoyed/jealous because of this, and you try congratulating him most of the time.

Jean:

   Jean has the infamous "cocky" attitude. He has days where no matter what someone says, he'll find a way to prove how he's better. Most of the time it involves Jean ranting on why he is clearly better than Eren.