[dxdm]

I understand where you're coming from, but please consider that not everyone is enjoying social situations the same way and to the same extent. For some people, being thrown into a surprise party as its main attraction is quite uncomfortable and outweighs the benefits of "cake and a break from work". It's more like "cake and a very exhausting kind of emotional work" for them.

They might not be much fun at such parties, yes; but telling them that they should enjoy them instead or that they are miserable people seems like a very unkind and unhelpful response to me.