Parents who have super high expectations for their kids can burn in hell. The only thing you need to do is find your own talent, forget the rest of school. Knowing your talents and capitalizing on them will get you oh so much farther in life then getting straight A's. In fact your high school marks hardly matter as long as you get your diploma. And anything below high school doesn't matter at all as long as you don't fail.
Also punishing kids for bad marks is the worst possible thing you can do. 90% of the time the kid won't try any harder and the parents just look like pricks.
From my experience the "perfect" students in school with straight A's and perfect attendance etc. tend to be complete morons. They know how to memorize facts and procedures, but that's about it. They are just generally stupid in any subject other then the ones they studied in school. It's not a good thing, as they barely go anywhere in life out of school. They are also often rejected from any prestigious universities. That being said some people get good grades and are intelligent but it's a lot less common. EDIT: By "...get good grades..." I mean "straight A's and perfect attendance etc." or similar.
And on a final note, extra curricular activities are your loving friend. They are often the best thing you can do if you want to get into a nice uni. (I'm talking more like math clubs and stuff, however nerdy that sounds. Sports teams don't matter but you should still play at least one sport.)
