There are certain words and phrases that have accumulated in cultural parlance for which the positive use is vestigial, but the negatory enjoys widespread use.
For example, whenever somebody retains their faculties through a surprising, or violent occurrence they are referred to as “unfazed.” But rarely do you hear somebody relate: “I was completely fazed!” Faced maybe, depending on their vices, but never fazed.
When was the last time you heard someone telling you how great requited love feels? Or described their composite mixture as adulterated? If irregardless is an incorrect version of regardless, what is the form one should use when they want to admit that someone’s point is valid, regardful?
Also there are words referencing a thing’s opposite that are never really applied to that opposite. People refer to old people as “Spry” to indicate that they aren’t bunched up or gnarled or stiff, but you never hear young people, commonly thought of as vigorous/flexible/gymnastic, referred to as spry.
What other ‘Uns’ or negative onlies can you think of?