The greatest set of 'beliefs' you can have. An Agnostic
belives that there is no way of knowing if God exists or not. Unlike religious people, who are usually neither intelligent or open minded, or Atheists
who are usually intelligent, but not usually open minded, an Agnostic is intelligent and open minded, smart enough not to be brain-washed into believing that there is a God who cannot be seen, but open minded to the idea that there may be one.
Most Christians will get very defensive if someone challenges that God exists, while some Atheists will treat every person who believes in God as if they are wrong, and there is no Gd and anyone who believes there is is stupid. Not all Atheists are like this, though.
A lot of Christians dislike Atheists and Agnostics because they have such a strong belief in God that they believe they know something for sure that no one can. What these people need to realise is that there is a very great gift that God, if there is one, gove us...free will. He gave us a brain which can think for itself and believe what it wants to...why wash it with things that some book or preacher say and make yourself believe it's the truth?