Always Changing wrote a good response - I'd recommend his answer over my own. Mine is just because I'm in a playful mood - completely self-indulgent...

Subtle signs of DID:

1. Waking up in bed with someone you don't know, that is not the same sex that you are attracted to.
2. Coming to in jail with no recollection of how you got there and no drugs in your system.
3. Getting off of work one day and heading over to a friend's house, not making it and the next thing you know, you're somewhere unfamiliar and no one speaks English in whatever country you're in.

You know, subtle stuff...