The biggest problem is that some dimwits will just continue to match or lowball you by €1 when they don't realize they can charge a higher fare and maintain 100% loads.
I don't understand how an airline can charge a higher fare
and maintain 100% loads. The only way I see this happening is if the airline switches to a lower capacity aircraft.
Personally, as long as my load factor stays above 85%, I don't bother changing fares. After that I start dropping fares in €10 increments. Also, I prefer to operate aircraft slightly smaller than the competition is flying. It allows me better operating margins, especially on crowded routes.