Maybe today wasn’t the perfect day, maybe it was. In any case: since the beginning of time and the temporal cycles of the universe, the sun has set—and risen—e-ve-ry day. Well yes, there are of course deviating parts of the world with longer periods of almost total darkness or where the sun doesn’t set. But let’s forget about them and stick to the point:
The Bible doesn’t offer us any estimate, but if we are to believe the Big Bang theorists, the universe, as we know it, was kick started around 13.7 billion years ago. Assuming that each year counts 365 days (forgetting the leap years of 366 days for the sake of simplicity), the universe is approximately 13.7 x 365 billion days old – and yes, this means that the sun has risen that many times!
If we use a deductive approach here, we assume that the sun will rise again tomorrow, as our empirical evidence suggests so. On the other hand, all swans are not necessarily white only because we have observed nothing but white swans. The observation of tomorrow might give us a black swan! The sun might not rise at all. But: do not despair! What are the odds for that? Less than 1 to 5,000,500,000,000.
My point is: tomorrow is (most probably) a new day! Thus, if your day didn’t turn out all too well, maybe tomorrow will 
Good night and sleep tight – with a smile on your face.
And for those of you who understand Portuguese: “Manhã, tão bonita a manhã – na vida uma nova cancão.” (Manhã de Carnaval).