They are ridiculously strict. Way more than other airlines. I have been hassled on flights out of ATH / CFU / CHQ etc... e.g. just being 1kg over and having to repack in front of the agent at checkin. Even on flights that are not even full. When connecting from a US or other international flight where they had no issue with the carry on, Aegean's strict enforcement is very annoying. So much so, i switched to SkyExpress - where they do not really seem to be obsessed with carry on weight.