This phrase irks me. it's like the speaker is delibratly ommitting "fun" or "nice" to psuedo-ambiguously imply that the rendezvous was unpleasant. I'm not certain that is always the intention, but I can't think of any other reason why someone would say it.

Apparently in parts of the east coast of the United States of America and perhaps elsewhere, this phrase is commonly used in a positive fashion, and is synonymous with "I've had a good time".