Don't format the card using a PC if your going to use it in a camera, only ever use the in camera formatting option.
It does funny things to the card and can mean you loose everything while taking photo even if you think you are saving them.
Agree... except there are, believe it or not, some cameras that don't have an in-camera formatting option.
Probably an accidental omission during rushed design... but still.... there are some...
e.g. BlackMagic Pocket Cinema Camera is one that I know of. But there are doubtless others.