Prehaps it was the diet of nothing but chocolate for breakfast.
Or maybe, just maybe it was this email;
>Got your money order today, thanks! I'll be putting your commission
>in the mail today, so it should be there in about a week.
Nobody will be able to ever tell exactly why Fionacat smiled happily and started to bounce manically in her chair (much to the distress of other co-workers and the HSE rep)