I complete these quite regularly. I'd like to think that KLM does read the comments of Quality Observers and seeks to act on them. I always used to slate the European Short Haul Economy catering ("sweet or salty") in Quality Observer reports and that got changed. I've also noticed improvements to Sky Priority boarding at airports where I repeatedly reported problems. Probably just a co-incidence in both cases, but if KLM has an army of regular customers who are all complaining about the same things, I'd hope such comments would hold some weight. FWIW, I do make a point of commenting on the 'culinary delights' served up in the Crown Lounges...