Adding on my earlier post, there's also a fundamental issue; most of the companies that dub anime works in their own language are in fact, companies which specialize in cartoon dubbing. For example, in Italy, Spain, Germany, US, and partly in Greece; the same people and companies who paid for cartoon dubs then would proceed to dub anime.
So you can imagine that those companies in the process also butcher certain plots and stories to cater more for their market, and perhaps even regional standards. Sailor Moon, Dragon Ball, and many other were reworked and then served to the wrong audiences.
The cultural barrier and the way the business works, and how most countries in the west portray the position of anime, and the current trends in the industry make it impossible to actually achieve a great quality in dubbing.