Is the f word is badest word in the world and important to the bad people?

Words are not bad. It is only social convention which makes it improper to say certain Words. The "f Word" may be considered to be a bad Word in English but a Word which sounds exactly the same has a completely innocent meaning in French (it means a seal, the animal which swims in the water). Most English speakers would think that there are worse Words than the "f Word".

Sometimes people want to show other people that they are not afraid to do bad things and so they say bad Words. For them bad Words may be important. But there are very very bad people who do not use bad Words at all. For them it is more important to be bad than to look bad to others.