I've never really liked April. Specifically, I don't like spring--but it manifests itself as an anti-April bias.
The light in April can be really harsh: you have the sunlight angle of August, without the softening effects of foliage. The ground can be muddy, and it reveals all sorts of winter-buried treasure like dog poo and corpses of small animals.
In university, I detested April because of the stress of final exams and overdue papers. Later in life, I got fired from a job, and lost two grandparents--all in a 10-day stretch of April.
Easter often falls in April. As a child, I perceived the holiday as a big disconnect: we're observing the death of Christ by painting eggs in beautiful pastel colours and eating chocolate.
I'm always glad when it's over.
"The tragic month of April" Wikipedia entry