Mine says, “Are we having fun yet?” And it usually takes 2-3 cups before I can say, “Why yes, I do believe so…” What do you like to wake up to?
My favorite mug is actually a clear glass beer stein etched with my company logo. I love stirring in a bit of sugar, removing the spoon and dropping in some cream and watching it swirl itself in. It’s like my meditative morning lava lamp.
They were selling them at work but I got one given to me as a kind of thank you, so I dig it even more because it was free. 
Coffee mugs are inanimate objects, and say nothing.
If your coffee mug starts talking to you, you may safely conclude that something more than coffee has been added thereunto.
Does that help?
Mine has a line going around it about halfway up, above the line it reads “Good Day” and below the line says “Bad Day”. It was part of a birthday gift from my best friend a few years ago. How well she knows me. 
I’ve got a variety of mugs, and like to vary them. The ones I use most are souvenirs from places I’ve been.
Except at work, where I often use mugs from previous companies I worked at…
My favorite says Puerto Rico
Boring. My favorite says Starbucks Coffee. I like it because a) it’s large, b) it has a soft touch handle, and c) the base is also soft rubber. Does it make things worse that I’m actually drinking Starbucks coffee out of it? Tastes pretty good, though.
Mine had a cartoon of Jesus on the cross and it says “T.G.I.F” on it. I don’t remember where I got it, but I have had it since University. It goes to the back of the cupboard when my Mother comes to stay.
Moo.
Dad.
Given to me by Mrs Piper for my first Father’s Day after the Cub arrived.
Nothing. My favorite mug(s) are the ones I got from Old Sturbridge Village and are hand made red pottery. We have 3 of them and if one is clean, I will use it before anything else.
Mine is solid black, just like my soul!
Mine used to be Me boss, you not, which was given to me by one of my girls. That’s no longer true, so I don’t have any words on my current favorite cup. It just fits my small hands and warms them up cause I’m usually a little chilly when I first get up.
Blue Bitch Bar. A cool place if you’re in heat!. Complete with their logo.
From the Blue Bitch Bar in St Maarten.
I have several. One says ‘everything tastes better with a little cat hair in it’. One is from my daughter’s college gift shop and we are fond of pointing out that mug cost us $75,000. But my favorites are from the wildlife association, with flowers and birds on them - cardinals, goldfinches, blue jays - because we are enthusiastic birdwatchers. Reminds me in the morning when I’m drinking coffee and thinking about some awful thing I have to do that day, that there’s still beauty and life going on outside my own sad little world.
This is my everyday coffee mug. I like it so much I’m on my second one - the first got broken and I missed it enough to buy another one.
Not mine, but I gave this to a friend a while ago:
I don’t put coffee in it, but my favorite mug says “Galileo” on it and has a diagram of JPL’s Galileo spacecraft.
My mug has 'S’s on it for Speedway gas station where I got it. It also has 32 oz. in several places showing the capacity.
Just two weeks ago, my daughter came to visit and left a mug that said, “The first cup of coffee in the morning recapitulates phylogeny.” I howled, but YMMV.