Quote 1
The father glanced down at the paper in his hand. He seemed to stiffen. He became very quiet. There was a silence. Then he said, "Say that again." (5.30)
Matilda's dad doesn't feel positive amazement here. Instead, he's horrified and stunned that she got the right answer. Rather than marveling at what a genius his daughter is, his immediate reaction is going to be that she must have cheated. He can't stand the thought that she could be smart, let alone smarter than him. What a nice guy, right?
Quote 2
"What the blazes are you all talking about?" the father yelled, putting both hands to his hair. "I most certainly have not dyed it! What d'you mean I've dyed it? What's happened to it? Or is this some sort of a stupid joke?" His face was turning pale green, the colour of sour apples. (6.27)
Seems like Mr. Wormwood is always turning funny colors, right? In the previous quotation he turned grey (4.41) and here he turns pale green. Both times, we see his fear written on his face through this change in color. We know he's scared because he looks so, well, ridiculous. This is not a guy who can keep his emotions in check.
Quote 3
She gave the hat a sharp yank. Mr Wormwood let out a yell that rattled the window-panes. "Ow-w-w!" he screamed. "Don't do that! Let go! You'll take half the skin off my forehead!" (3.5)
Although Mrs. Wormwood is trying to help her husband, we're thinking she probably could have done so a bit more gently. To be honest, though, Mr. Wormwood's reaction is equally ridiculous and extreme (although, to be fair, he probably wasn't expecting it to hurt so much). Do you think it's more likely that Mrs. Wormwood is surprisingly strong, or that Mr. Wormwood is a total wimp?