Nothing bugs me more than a great horse with that one blemish - a second
Getting a perfect record from my horses from 2 to the end of the 4yo season still is a good challenge even when you always breed monsters. I have 244 in my transfer pool and maybe 5 or so have undefeated records with their campaigns usually lasting between 15 and 20 races. I manual train also so that makes it harder - but more satisfying.