If I go to the Opportunity Tab of a Contact (or Company) which has say five opportunities listed and double-click one to open it in Opportunity Detail view I intuitively expect that the left / right arrows will now take me to the other Opportunities from that same record.
They don't. Every opportunity is selected.
This is inconvenient because to see detail of the other Opps from the same Contact in detail view you have to close one down then select the next from the tab.
Selecting all the opps from the Tab then Create an Opportunity Lookup goes some of the way, but leaves you in List view which doesn't show you anymore information than you had originally. And that's four extra clicks.