Calculating time differences correctly is challenging. With more than two dozen time zones at play on any given day around the world, and yearly / historical fluctuation in time, it's no wonder that Salesforce stores dates in GMT and tries to enforce good practices surrounding time and date calculation by giving you -- the developer -- quality date/time APIs when dealing with them. When working with formula fields in Apex, however, the developer must keep in mind certain idiosyncracies in ord...
