I have never, since age 10 or 11 years old, had anything other than either a Pepsi (a long time ago) or a cup of coffee for breakfast.
When I smoked...add a cigarette or a cigar to the beverage.
No lectures, please...and no apologies.

Very European.
Now,
@Apple fanboy, I will tell you when this started,
@Shrink's post has just reminded me of the circumstances.
When we were kids, my father got us up; Mother never had breakfast with us - she planned her day while we were eating, and got up after we had left for school or work, (in the case of dad).
Unlike her, he was a morning person, and he used to superintend our breakfast until we finished school. (That included cereal, - muesli for me - boiled eggs, toast, and coffee for me, even as a teenager. Brothers had tea or milk.) From a very early age, we were taught to prepare our own breakfasts, say, from the age of six or so, with dad superintending the process.
So, right through school, and right through undergrad days, I always ate a good breakfast, and accepted fully the stuff about setting yourself up for the day.
Then, I started teaching, and the first year I taught,- in fact, the first few years I taught - many of my classes were at 9 a.m. I always put a lot of preparation into my classes, not just academic but.....I suppose you would call it psychological. In essence, you are giving a 'performance'; I was and am an excellent public speaker, but - even now - with vast experience and considerable confidence - I will not address an audience on a full stomach.
I got into the habit having a coffee before I left the house, then teaching my classes, and then, having a late (and very enjoyable) breakfast afterwards.
As a university teacher, -
@Shrink's post of coffee and cigarette reminded me (though I never smoked), but I know that mental landscape - I had been known to bring a cup of coffee, plus saucer, into lecture theatres, to the stupefaction of my audience.
More recently, I had to give political briefings most mornings after the 'morning brief'. That meant up, and showered, at least an hour before delivering my briefing in order to be on top of stuff. Unless the coffee is pre-ground(and the coffee shop wasn't open that early) there was no coffee.
Again, a large - late - breakfast, (fried eggs, bread, fruit, plenty of coffee, and freshly squeezed juice) - when I would have been up about three hours - tended to follow my briefings.