You already know what a messenger list of Yahoo Messenger is. When we met someone in chat room or else, we usually add an ID or user name of someone who want to be our friend.
It is important for us because when we are online in other time or your friend online, we can see he or she being online.
Thus, we can chat with her or him. But sometime if we want to delete her or his ID of yahoo messenger, we just take one step and delete her ID.
In this case, we only delete her ID from our messenger list but our ID still saved in their messenger list. Consequently, they can see when we are online or not but we cannot see he or she online or not.

If you want absolutely disappear or remove your ID from their messenger list, there is software developed to work with this purpose.

It makes me sick to see the screen shake and it seems like I am going to pass out when that happens.

The good news is that you can disable BUZZ!! and shake.