There is some truth to that statement. Several years ago I met a family who had one kid that was just driving them completely nuts. I mean, bonkers nuts. I simply told them, "well, you don't have enough kids. If you had one worse than him, you'd hardly notice him." I said it, tongue in cheek, but then they adopted a sibling group of 5 and a year later mentioned to me that they hardly even remembered how bad the original kid used to bother them.
My reason for being glad I have so many kids is that at least one of them loves you ever day. This morning, after Salinda had gone ballistic verbally, all over me, Sadie and Dominyk left for the bus.
"By Mom. I love you. Have a great day."
So see, if your kids are making you miserable, it's because you don't have enough yet. I can tell you how to get some more. ;-)