Usahara is in an interesting situation...He's pretty sure he's dating you, he asked you out, you said yes, you both had an amazing date, and the next thing he knew you two were together...When you get into work mode though...He's afraid of you...

Your smile is scary, your intimidating words make him think he's gonna get fired...He's terrified of you, but he loves you, so he takes your scary work mode like a champ, because he knows you're going to shower him with love, and affection later...