it too serious, perhaps. It really depends. If you are giving a speech or lecture in public,
use it only occasionally (Even Bill Clinton used it occasionally); if you are talking with a close friend or friends, you can use it as often as you like.

you know the pharase 'you know' can convey a variety of meanings. The key is to use it
when it is approriate and use it in a way that really conveys the meaning intended by you.

For most of us, we only use it as a pause so that we can have time to search for the
next english word or thought. This is also fine. Do not hate the phrase too much,
because it is just a scapegoat of our imcomptency in the english language.

hehe.