It’s not a matter of good vs evil
There are good discounts.
And there are bad discounts.
And the difference between the two is always to do with how the customer requests the discount.
The biggest bad discount issues I see are a competitor with a higher price as a justification for demanding a discount (your competitor offers services that are unique to them as much as the services you offer are unique), and a customer that is unwilling to commit demanding a discount to get them in the door.