Once you have two kids a third's not a big deal

I've often heard people say that once you have two a third is not a big deal....my guess is they weren't talking about going from one to three in one shot.....who knows. What I DO know is that when we have two kids on our hands and not all three, life seems like a piece of cake...
This morning Abigail and I went out to run a few errands and had a good time. I got home and suggested that we go out to lunch with everyone, including Nana, to a restaurant that I can't stop talking about : The Casual Gormet--great food, large portions!! but anyway --WHAT was I thinking. Abigail was difficult from the minute we got in the restaurant which then got me jazzed. Then while eating she was the WORST she has ever been in a restaurant ( it wasn't a new place) she had a miserable time and I felt so bad for the other patrons as she just screamed, not once but three times, all because parts of her sandwich fell on the floor and she spilled her milk. Which then of course not only got me upset, mad, embarrassed but the boys also could feel the tension and started getting cranky. That was just the beginning of our rough afternoon. We then got home and the boys wouldn't calm down for naps. Justin is teething and me going in to deal with him, disrupted Ryan and he started screaming. Abigail also chose not to take a nap, but Nana had the joy of dealing with her because Justin and I were out at PT.
I guess my point to all of this is that as I've mentioned before things go down hill so quickly and snowball out of control. Often it feels like it happens out of no where for no reason. When there are two kiddos, life seems manageable even easy on most days, (even if two are screaming-but adding the third in just seems to put it over the edge) This isn't to say we don't have good days--we DO lots of them, with lots of hugs and kisses and sounds of laughter. However today was NOT one of those days..today was tough, today was trying and it really made me wonder who thought that if you have two kids adding a third is no big deal...my guess is they weren't talking about one plus twins!!