There was an important job to be done and Everyone was sure that Someone would do it.
Someone got
angry about that because he thought that it was Everyone’s job.
Everyone thought that Anyone could do it, but No-one realised
that Everyone wouldn’t do it.
It ended up that Everyone was
angry with Someone because No-one did
what Anyone could have done!
This is a different way to explain and understand
indefinite pronouns. Here you will find some grammar notes if you prefer a
traditional explanation.