why my wife is so mean to my son?

i dont know whats happening. my wife has been mean to my son lately. i guess she's mean, but i know she is just correcting my son because he doesn't listen. when i was a kid, i remember my parents were really mean to me, i would get in trouble a lot because i forget to do things like pick up after myself. now that my son is 4 years old, i see the same thing happening to my son. it breaks my heart to see it, because i want to stop her and tell her not to do it anymore.

i spoke to her about how i feel, and we ended up arguing with each other about the subject. so the next day she told me to watch for my son and see how it feels. so i started the day by making him breakfast, when i told him to go sit down, he kept stalling and i had to repeat it to him 4 times to go sit down. i realize why my wife gets aggressive with him, because if you are nice, he doesn't listen.

i dont know what to do. i can see its affecting my wife. her attitude is different. i want to see her happy again. i guess i should be happy because she cares about our son and that's why she is always correcting him. but i can't help feel sorry for the kid.

im wondering if other dads are going through the same thing or am i alone in this? i want to help my wife and my son. i just wish could find a balance.

can you give me some advice, or am i just crazy?