Of course, my friend.
As in the Yin and Yang, everything good has something bad and vice versa.
What happens is that this “something” is usually very intense.
A negative example, my breakup with my partner, burst me inside, but the good spot of that so black, was my return to writing.
Now an example of a dream fulfilled,
I published with the biggest publishing house in the world, the same publishing house where my favorite authors publish, black point “they promote them, not me”.
Moral: it always happens. But you can't stop dreaming. Because it's always better to have a BIG dream with a black dot, than not to have it :-)