Not sure a stressful experience which however does not result in missing the plane should be allowed to ruin a holiday. My experience with MAN T3 is that service levels both at check in and security are quite variable at the same time of day--- you can be through both in 20 mins or it can be well over an hour. So the best way these days is to arrive two hours before the flight time and accept you may be sitting about or you may not. I can't comment on EMA but at Leeds I wouldn't like to allow less than one and a half hours at peak time if you're not going to pay for fast track.
I've been in much worse queues at hub airports in the States!