Watch out when deleting user with "limited access" permission

Ok, So you see all the time in your root SiteCollection web site users with the weird permission of "limited access". Sometimes you don't even remember why they have this permission and you just want to delete them... So BIG NO. You are about to create a major mistake.

Before I start to explain why, you need to understand what is it.

Limited Access is a permission level that is automatically assigned to a user or a group when you assign them a role at a lower level ( website/list ) but in order to access that lower level they require to access an object at a level higher than they have permissions to ( like the top rootsite of the SiteCollection ).

When you delete that user who has limited access permission from the permission list, you also delete the user from the list/site/item that he does has permission to ! Yes, by doing this small step, you delete the user actual permission from the subweb/list.

Be aware when you want to delete this permission.