Rumours can be amazingly helpful.
For example, it would be wonderful if a rumour spread about how amazingly funny and witty I am and how people should flock to this blog.
On the other hand, rumours can be less helpful.
Such as, for example, my friend sarcastically told me she was pregnant, very loudly and in the middle of a Physics lesson.
That particular one caused the teacher to take her seriously, inform the school nurse, and my friend was invited to a meeting about her options for the baby which culminated in her shouting ‘I’m not pregnant‘ at the nurse.
Moral of the story: Don’t ever say you’re pregnant within earshot of teachers. Particularly if they’re inclined to think you might actually be pregnant.
Moral of the story #2: Don’t make all your teachers think that you’re the kind of person who would actually get pregnant.