Alright I'm getting so angry now! Every time my granny is here, she doesn't let me reboil the water in our kettle... she said reboiling water causes cancer! I've never heard it's bad, I thought reboiling water actually kills more bacteria that might form when the water becomes warm.. so you need to reboil it. I'm too lazy to refill the kettle with cold water and boil it again.. reboiling is much more convenient! I mean it's water after all, so how can it be bad? Please tell me I'm right!!