Reasons I've been yelled at in the last hour:

Because I left him in the playroom to go get her.
Because she wanted water instead of milk.
Because she wanted milk instead of water.
Because he tried to sit on my toe and fell off.
Because she tried to sit on air and fell off.
Because she gave me a book and I read it.
Because she gave me a book and she wanted me to read a different book.
Because he gave me a book and it had the wrong words in it.
Because she gave me a book and I didn't read it.
Because he gave me a book and it wasn't the book she wanted me to read.
Because I tried to read both books at once.
Because she wiped her snot on my shirt and then couldn't get it back.
Because I said "ow" when I got four elbows to the stomach simultaneously.

Because I put them back in bed, since clearly they weren't ready to get up yet.