Superfluous means an excess /a surplus/ too much/ not necessary. Example: After confirming your email id, the need to confirm your phone number as well, seems superfluous to me. Superficial means to be emotionally or intellectually shallow. Example: Paris Hilton is often regarded as a superficial person.

‘Having a cake after that big meal was superfluous’ means that it is more then you need. ‘I thought he was nice, but his kindness was superficial’ means that it only seems that way on the surface, when you find out more about it, you realise the truth is different.

Superfluous means something is more than needed. Example. Do not order any more paper. We do not need more. It would be superfluous to our requirements. Superficial means on the surface, not deep or of much true meaning. Example. Those comments are superficial. Try to use more meaningful arguments that will change our ideas.

superfluous: more than is needed or wanted (the report was marred by a mass of superfluous details) Superficial :( of a person) never thinking about things that are serious or important: for example; He's fun to be with, but he's very superficial. Or not complete and involving only most obvious things