Apparently, David Faustino and Seth Green get confused for one another regularly. Perhaps it's our eyesight, but we really can't see that at all. They don't have the same facial shape or hair color, and nor do they sound the same. In fact, there's only one physical characteristic they have in common at all as far as we can see - they're both considerably shorter than most of their male acting peers!
Faustino's movie work hasn't been anything to write home about, but he's had a very successful career on the small screen. 'Married with Children' is his most obvious hit, in which he's played 'Bud Bundy' for years, but he's also been in 'Bones' and 'Little House on the Prairie' among others. You'll notice in this picture that he's wearing some seriously big soles on his boots - that's because he's only a tiny 5 foot 3, and so if he didn't do that he'd be face-to-chest with almost everyone he met.