The real problem is that the heuristics that Mail.app and Gmail use to determine which emails constitute a thread/conversation are slightly different. That mea

The real problem is that the heuristics that Mail.app and Gmail use to determine which emails constitute a thread/conversation are slightly different. That means that GMail might count ten messages as being part of a conversation, but Mail.app will only count 8 of those as being part of the same thread. It seems minor - but it's really infuriating when you try to switch back and forth.