Now I have said to someone "You sound tired" and have had it said to me when I was legitimately tired. Like a PP, I don't have much of a poker face at all and pretty much wear my emotions on my sleeve. Heck, my best friend can accurately guess my expressions over the phone by the tone of my voice. So I'm very expressive, I guess.
About 3 years ago I worked at the Maryland Renaissance Festival and after my first day working there I called my best friend. Now when I'm really tired I have a hard time finishing sentences. So I was chatting with my friend as I was trying to find my van and was saying things like "Well I just need to find my-my-oh there it is. Van, yeah, found the....van." So yeah, I was tired.
When I went down to Paris Island to see DH when he graduated from boot camp, after the ceremony we were walking along arm in arm and he looked at me and said "You look exhausted." And in all truth, I was. I was so excited to see him that I hadn't slept well in the previous few days. So I wasn't offended.