Five settings that change what you see every day, in one place.
Gear icon → My Settings. Role: which role centre and which page customisations you get (Accountant, Sales Order Processor, Warehouse Worker...); change it to see the system the way another team sees it. Company: your default company at sign-in. Work Date (tip 9). Region and Language: date and number formats, and the language of every caption. Notifications: which blue-bar notifications you want (tip 41). Teaching tips on or off.
If a user "sees different pages to me", the role is the usual reason. If dates look American, region.