Richie Rich
Without strife, your victory has no meaning.
Without strife, you do not advance.
Without strife, there is only stagnation.

Problem Child

Ruthie in
Two for the Road
(1967)
Jean-Louis Gaudel, the little French boy in
Charade
(1963)

War Of The Worlds…that girl screaming constantly….grrrrr.
Ho Ho Ho

Most of the Spielberg kids.
Short Round in
Temple of Doom.
I wanted Indie to stuff that insufferable rugrat into a cannon and blow him into another dimension.
Tom Cruise's son in
War of the Worlds
has already been mentioned. I wish Spielberg had had the guts to kill off the whiny s-o-b when he ran off to join the war.
Every smart-ass movie brat who knows, or thinks he knows, more than the adults and spends the entire film telling them about it. The boy in
Jurassic Park
fits that description.
If you have seen
Dondi
(1961), you know what I'm talking about. If you haven't, don't.
Aneta Corseaut's little brother in
The Blob
. Why director Irvin S. Yeaworth gave the part to a non-actor is beyond me. He was awful.
And This, Too, Shall Pass Away

Spielberg's War of the Worlds. Especially the son.

As much as I like T2 and don't consoder John anbad character, he is annoying.
ᴳᵒ ᶠᵘᶜᵏ ʸᵒᵘʳˢᵉˡᶠ

Richie was the best though, but overall I prefer Ben. I was Ben as a kid.
ᴳᵒ ᶠᵘᶜᵏ ʸᵒᵘʳˢᵉˡᶠ

The Goonies (1985)
IT (2014/2017)- Not all of the kids. Just those screeching non stop yelling brats who played Eddie and Ritchie.
You asked a pretty question; I've given you the ugly answer.
Fasten Your Seatbelts….
It's Going To Be A Bumpy Night!