I’ve got one of those magnetic screens and they work well but get in the way so I sometimes forget (don’t bother) to attach them when my French windows are open. The buzzing fly is bad enough but what really turns it into a trauma is the trail of destruction caused by my cat’s grim determination to catch the darn things. He shoots about, knocking things off shelves, spilling my coffee, clawing up the curtains and using me like a piece of furniture to be clambered over. He has never, ever caught one.