Something that I enjoy is being the anti-Karen. I most often do it by email, but occasionally I speak to the manager in person, and I say that the service I received was exceptional. Sometimes I leverage my autism in this, because if I have had a good experience, there’s a decent likelihood that the additional struggles due to being autistic are a component in my gratefulness. I always make sure to get the name of the person who helped me so I can reference them in the anti-complaint, because I know that a glowing review from a customer can make a huge impact when it comes to performance reviews, bonuses and promotion

Important tip: if someone gives you free stuff or a discretionary discount, no they didn’t. You can still effusively praise the service you received, but do not mention the free stuff, because that can end up having the opposite of your intended effect and result in the helpful and kind person being chewed out by the manager