Personally, I don't have a lot of trouble taking tests, even high pressure state standardized tests. Most of the time I don't do my homework, I rarely study, but in class, all we do is review, reteach, go over things more, (in science
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do labs, and talk about how such and such works. That's almost all we do in class, so I usually have no trouble on tests. Surprisingly, however, almost everyone I know complains about how hard they are, and they are the ones who always turn in their homework.
I think the key is that if it is possible for students to absorb knowledge so well in minimal amounts of time and retain it well without even extra practice at home, then this opens whole new opportunities for schools. I know a few people at my school like this too. The only problem is the way the knowledge is taken.
When I listen to people talk about how they hate tests, I also ask how a normal class period goes for them, and they talk about their teacher's personality, how cool they think they are, funny things people said, embarrassing moments of being called on and not knowing what was going on, and what they were thinking about while the teacher was talking at the class.
The main problem here, is that schools don't have an effective way of keeping the class's attention, or at least, keeping it enough.