This is so common. People often click an Incident for example and click Delete View thinking it will delete the work item but instead it deletes the view. This is easy to resolve without having to create the view yourself again.
All you need to do is import the default management pack again
NOTE: If you saved any customizations to the unsealed management packs you could potentially lose these by using this method. Instead create the view manually!
Open the Service Manager console and navigate to Administration > Management Packs > Import (under tasks)
For Service Manager 2016 navigate to “C:\Program Files\Microsoft System Center\Service Manager\System Center Management Packs\Unsealed Management Packs 7487” and select the “ServiceManager.IncidentManagement.Configuration” Management Pack and click Open.
Then click OK
Close and reopen the SM Console and the default view you deleted should be back . If not, restart the SM Services in the Services MMC.