From CSI Las Vegas 404.
Context: There was a case that a baby was dead in a car in the morning and a forensic doctor joined the case.
Detective A: Heard you had a rough morning.
Forensic Doctor: I've had better.
I don't fully understand the meaning of "I've had better". Does it mean 'so,so' ?
It doesn't necessarily mean that the doctor's day is going well, or even so-so. The doctor is masking his true feelings by saying the equivalent of "yes, it's bad, but eh, I just have to deal with it."
Based on the scenario you explained, it sounds like the forensic doctor could even be trying to be humorous. His day has definitely been horrible. So when he says "I've had better", he's agreeing with the detective ("Looks like you had a rough day") and may be trying to be a bit lighthearted. Of course the doctor has had better days! In that sense, it comes across a bit like a joke.
It's elliptical, that is, it drops words that are understood by native speakers.
I've had better mornings than this one.
It's an understatement for rhetorical effect.
The doctor is using understatement.
"I've had better" in response to "I heard you had a rough morning" means "Other mornings in my life have been better than this one," that is, "This is not the best morning I have ever had." That is not a very strong statement; strictly speaking every single morning in your life has been "not the best," except the one single morning which was the best.
What the doctor really means is "Yes, this morning was very bad."
Literally, I have had better [something], meaning I have experienced better (than this).
I have had better (days) [days which didn't suck as much as today].
I have had better (food) [this food doesn't taste that good].
It can infer a little bit of cynicism or irony, but mostly is a kind of quiet way to complain without being mean about it.
