You convey a lack of confidence or, worse, that you are concealing something when your eyes flicker around or you turn your head away from your speaking partner or partners.
It is impolite as well as angry. It shows a lack of interest when someone leans over and begins chatting with the person next to them or spends the entire meeting answering emails.
We all have important things to say, but please hold back. Hold off on sharing your thoughts until the conversation has paused appropriately. Interrupting is impolite.
For those listening, using words like "like" and "um" is distracting. As we translate our ideas into words and sentences, we employ them because we find silence uncomfortable.
Naturally, there are occasions when prudence or worry are justified, but if you are always pessimistic, your coworkers will avoid you and not pay attention to you when you may have crucial information.
If someone else is gossiping, leave them alone or, better yet, interrupt them and bring up another topic. Don't tolerate and don't participate.
Always reply to emails promptly, and if you are unable to do so, state that you are awaiting information from someone else, etc.