Terms often have relative meanings. Pre-Harry (our newborn), my definition of tiredness was :-
bleary eyed and a feeling of exhaustion.
Post-Harry, tiredness means :-
waking up to discover I've put my iphone in the fridge and the butter in my briefcase.
It's impossible to describe how all the tiredness, messiness, anxiety, stress, the "I can't cope!" moments and uncertainty are paid off in a single smile - but they are.