I think it is very debatable on how Malaysian drive, but I belief that this affect the productivity of its people. All do respect, I am personally a pretty fast driver, but expects to be safe. I hate to do those zig-zag if I do not have to, or I hate to drive very near the front car to make the change lane. But sometimes it really hard not to when you see those people hogging the lane as much as they like.
I think that the right lane is always for overtaking only, therefore, if you are slow/fast you will always have to give way to the faster car. But in Malaysia those kiasu fellas would rather drive at their own pace and block the road. I think that Malaysian are much more kiasu in terms of driving than anything else.
Do you notice that in Malaysia, when you encounter a 3 lane highway, the middle lane is always the slowest. It is actually quite typical, which is another reason people zig-zag around the road.