What surprised you when you first became an engineering manager at a startup?

I hired an engineer yesterday, which makes us a two-person startup, and me a manager.

I've worked as a software engineer for almost a decade at a giant company, and mentored multiple junior engineers and interns, but I was never a people manager, and in any case, things are different in a tiny startup as compared to a giant company.

When surprised you when you first became an engineering manager at a startup?