My cat is very aggressive towards me when I clean out his litter box. I have the door shut when I do it but he still exhibits aggressive behaviour for about 30 minutes after. Generally *aside from an incident with a dog and a raccoon he isnt like this. 3 years, neutered, recently vet checked male with no health problems. I clean the litter every day and change it over entirely once a week. We have a feliway diffuser in the house (not sure how much it helps)
He is the only cat in the house and there have been no changes in the household that might account for anxiety or aggression.