Its always bothered me that the bible is open to saying things like "oh in the original language it says something totally different than the way the authors translated it." It's interesting that it can mean something more positive, but it was translated the way it was. So why should I believe that your translation is right and the scholars who translated it were incompetent?
On top of VH response, different translations work towards different goals, the NASB works towards being a more literal, scholarly translation which can make it a tad less understandable as t's intended audience is for people who will be using it in a research oriented manner.
The English standard version seeks a more common tongue approach where their goal is less to present a word for word accounting of the text and instead produce somethings that is easily read and understood while retaining as much of the of the authenticity of the original text as possible. It can be contrasted to the message which isn't a translation but instead an interpretation of the original texts that are then written out in common English while retaining a narrative format.
On top of all that most of the language simply flows differently in Greek and Hebrew and it's hard to catch all of the meanings of a words in english especially when those languages have four to five words for concepts that we only use one word for(the four Greek loves are a great example as well as the Hebrew words for spirit ). In those cases it's not the translators have done a bad job it's just that English is inefficient at relaying the meaning of the text(oh oh Crown that's another good one, the Greek has multiple words for different crowns that we tend to only use the one word for).
That's on top of the sectarian and denominational bias that people bring with them that VH mentioned.
So yeah, look at the Greek yourself, Strong's has an online concordance with all of the Greek and Hebrew words used along side of how often their used, where their used and different definitions that are available for the one word.
I'd also like to end this with the note, in most cases your Bible isn't so terribly flawed that you should never read it again or fear that you have to check a concordance every time you open it. They get all of the major points across and are still very much usefull in learning about God, Jesus and the Gospel. The people who are in charge of translating the texts are often of the mind to do so with as little of bias as possible some even come from a multitude of backgrounds so as to even out it any inherent bias from the group.
Edit: thought of another good example of the differences is Matt 3:9 the words Jesus spoke would have been in Hebrew, and he mentions God making son of Abraham out of stones. In Hebrew the word for son is Ben while the word for stones is Eben, Jesus was rhyming in that verse and it's something we would completely miss in the English. Even if it's not exactly important to the salvation of man it's still something to think about, Jesus chose words in particular fashion to convey his messages and to drive home his points, he was after all a preacher.