I certainly see this in Perl all the time:
  $self->total( $self->total + 1 );

Before automatically writing this off as being bad code, consider:

• The class has--or appears to have--a public accessor and a public mutator for total.
• The mutator is free to do stuff other than setting total. For example, it might log that fact that total has changed, or it might notify other agents who have registered interest in that aspect of the the instance.
• Subclasses are free to add interesting behavior to mutations of total, even if those mutations are generated internal to the class.

By coding this as   $self->{total}++; you lose these benefits. Sometimes these benefits aren't important, sometimes they're vital. That said, perhaps   $self->increment_total; might have been better.