"Perfect" isn't a loaded word here, it just means maximally rational.
Take 2 bundles of products - A & B. They both cost the same, but bundle A would bring you 2x as much joy/utility/whatever-you-want-to-call-it than bundle B. To choose bundle B would be "less good" for you than choosing bundle A: that's what irrationality is...by definition. Choosing A is the "most good" option: that's what rationality is. Someone who chooses A over B 100% of the time is a "perfect consumer".
Take 2 bundles of products - A & B. They both cost the same, but bundle A would bring you 2x as much joy/utility/whatever-you-want-to-call-it than bundle B. To choose bundle B would be "less good" for you than choosing bundle A: that's what irrationality is...by definition. Choosing A is the "most good" option: that's what rationality is. Someone who chooses A over B 100% of the time is a "perfect consumer".