Confusion regarding 'sharing' your schedule with other team members or subscibers. Seriously, would it kill them to put an 'added', 'enter', or some kind of 'task completed' button... it would save a lot of confusion. Sending an invite to fellow workers results in a vague link that seems disconnected with the original intention. No 'Connect with Users' or anything other than a link. For something that's supposed to be time management related, I've wasted hours trying to figure this out.