"Unreasonable expectations" refers to having demands or hopes that are not fair or realistic. It means expecting more than what is reasonable or possible to achieve. Full definition
Where this does not happen, then challenging unreasonable expectations about marking will help reduce unnecessary workload, while also enhancing teaching and learning. (neu.org.uk)
With little time and competing agendas, schools often hold unreasonable expectations for what teachers can accomplish. (ascd.org)
Almost every lawyer has experienced a client with unreasonable expectations, or one who got bad results because of their own bad behavior or bad facts. (lawyer-coach.com)