Embarrassment is a really weird emotion. It’s related to shame, but it’s not exactly the same. Shame is an emotion you can feel about something even if no one else knows about it. It’s connected to your internal sense of right and wrong. Which isn’t to say that shame can’t be influenced by outside factors like cultural norms, religion, the disapproval of others, etc. But whether originating from without or within, shame is about how you feel about what you did.
Embarrassment, on the other hand, is entirely about how you feel about what other people saw you do. And it’s not even entirely about right and wrong. Sure, you can be embarrassed about getting caught doing something shameful. But you can also be embarrassed about being seen doing something that is totally an accident and not your fault, like tripping on the sidewalk or a bird pooping on your head. Those are misfortunes. We worry people will judge us to be clumsy, or our condition will revolt them. We’re not even sure why we feel so bad. We just do. And the feeling can be really intense, even about something relatively trivial -- as strong or even stronger than the shame we feel about having intentionally harmed someone or failed in a responsibility. Most of us probably still cringe at the memory of some embarrassing moment that happened when we were children, despite our adult knowledge that it was no big deal and is in fact a common occurrence in children (like, say, peeing the bed or forgetting a line in the school play).
The downside of being social creatures, I guess. Humans are weird.