As someone said earlier, no parent is perfect.
My son is only 8 months old and yes, I've been driven nuts by him sometimes, but I don't shout at him or swear. I just pass him to hubby and go and have a bath or something, lol!
But as I mentioned earlier, I used to be very judgemental about other peoples parenting practices until I had my son, even from little things like babies with dummies (until I found out how useful they can be for an overtired baby).
But I also have a nephew of 2.5 and he is into screaming, kicking and biting.
My sister loses her rag with him a lot more now and can end up raising her voice, just as her partner can.
Actually she said to me this morning 'He used to be such a good baby' and I think she made a good point.
Babies change into toddlers. As we all know, toddlers are hungry for knowledege and can therefore be quite demanding. But they are also learning to assert themselves, so yes they will drive parents nuts.
Anyway, I'm rambling, but I suppose what I'm trying to say, is that most people have children with the best intentions, not fully understanding that these are little humans who will constantly change and sometimes the results of those changes can be too much at times.
There, I'll shut up now!