Why do people come to class when they’re sick?

I get it—sometimes it's unavoidable. If there’s a mandatory session, an exam, or something that absolutely requires your presence, it makes sense. But if that’s not the case, why put yourself through the trouble of sitting in a crowded classroom with 60 other people while coughing the entire day? Maybe it’s just me, but after the pandemic, I’ve become extremely cautious around sick people. If it’s just one person, it’s manageable. But when I walk into class and see at least 30% of the students visibly sick—someone or the other constantly coughing—it gets overwhelming. We’re all packed into a closed room, breathing the same air, and it starts to feel suffocating. What makes it worse is that my college doesn’t even care about attendance. There’s literally no reason to show up when you're unwell. So why do people still do it?