(XNA - Farseer) Not always colliding and moves seemingly randomly then objects freeze if they do collide

Question

So I'm mixing XNA and Farseer, the first for graphics and the latter for collision and physics. If this is a horrible choice to start out with, tell me that as well.

In any case, I have set up a entity class upon which I build my other classes (players and enemies). However, none of the functions in Farseer seem to work. Nothing related to physics that is. I can walk through a box, my bullet gives no collision detection, nothing.

Main:

public class Game1 : Microsoft.Xna.Framework.Game
{
    GraphicsDeviceManager graphics;
    SpriteBatch spriteBatch;
    World world;

    //Create a lists
    List<Entity> entityList = new List<Entity>();

    //Player
    Player player;

    //Target
    Target target;

    //Others
    float framerate;

    public Game1()
    {
        graphics = new GraphicsDeviceManager(this);
        Content.RootDirectory = "Content";

        graphics.PreferMultiSampling = false;
        graphics.ApplyChanges();

    }

    protected override void Initialize()
    {

        //Create world
        world = new World(new Vector2(0f,0f));

        base.Initialize();

    }

    protected override void LoadContent()
    {
        // Create a new SpriteBatch, which can be used to draw textures.
        spriteBatch = new SpriteBatch(GraphicsDevice);

        //Create player
        player = new Player(BodyType.Dynamic, Content, entityList, world);
        entityList.Add(player);

        //Create target
        target = new Target(BodyType.Dynamic, Content, entityList, world);
        entityList.Add(target);
    }

    protected override void UnloadContent()
    {
        // TODO: Unload any non ContentManager content here
    }

    protected override void Update(GameTime gameTime)
    {

        framerate = 1 / (float)gameTime.ElapsedGameTime.TotalSeconds;

        // Allows the game to exit
        if (Keyboard.GetState().IsKeyDown(Keys.Escape))
            this.Exit();

        //Update the world
        world.Step(0.3333f);

        //Update players and entities
        player.Update();
        target.Update();

        base.Update(gameTime);
    }


    protected override void Draw(GameTime gameTime)
    {
        GraphicsDevice.Clear(Color.DimGray);

        spriteBatch.Begin();

        //Draw target
        target.Draw(spriteBatch);

        //Draw player
        player.Draw(spriteBatch);

        spriteBatch.End();

        base.Draw(gameTime);
    }
}

Target (child of Entity):

class Target : Entity {

    public Target(BodyType newBodyType, ContentManager content, List<Entity> entitylist, World newWorld)
        : base(content, entitylist, newWorld) {

        //Get texture
        Texture2D texture = content.Load<Texture2D>("Enemies/Target");

        //Create farseer object
        Body body = BodyFactory.CreateRectangle(newWorld, ConvertUnits.ToSimUnits(texture.Width), ConvertUnits.ToSimUnits(texture.Height), 1f);
        body.Position = ConvertUnits.ToSimUnits(new Vector2(300f, 300f));

        Fixture fixture = FixtureFactory.AttachRectangle(ConvertUnits.ToSimUnits(texture.Width), ConvertUnits.ToSimUnits(texture.Height), 1, new Vector2(0f, 0f), body);
        fixture.UserData = "Target";

        //Set other stuff
        setWorld(newWorld);
        setBody(body);
        setFixture(fixture);
        setTexture(texture);
        Update();

    }

    public void Update() {

    }

    public void Draw(SpriteBatch spriteBatch) {

        spriteBatch.Draw(getTexture(), ConvertUnits.ToDisplayUnits(getBody().Position), null, Color.White, getBody().Rotation, new Vector2(getTexture().Width / 2, getTexture().Height / 2), 3f, SpriteEffects.None, 1f);

    }
}

Entity:

class Entity
{

    public List<Entity> entityList;

    //Get physics stuff
    Texture2D texture;
    Fixture fixture;
    World world;
    Body body;

    public Entity(ContentManager content, List<Entity> entityList, World world){

        this.world = world;
        this.entityList = entityList;

    }

    public void Update() {

        fixture.OnCollision += entityCollision;

    }

    public void Draw(SpriteBatch spriteBatch) {


    }

    public bool entityCollision(Fixture f1, Fixture f2, Contact contact) {

        Console.WriteLine("Collision detected!");
        Console.WriteLine("F1: " + f1.UserData);
        Console.WriteLine("F2: " + f2.UserData);
        return false;
    }
}