Focus and Attention Span
The attention span of a two-year-old is variable and is very much subject to his moods. Although less easily distracted than he was at one, he will generally spend only a minute or two looking at any one thing.
At the same time, sometimes your child will become fascinated with an object and be unable to let go of it, both literally and figuratively. If it's small enough, such as a little toy, he will want to hold onto it and maybe sleep with it. If it's safe for him to do this, let him. If not, together find a safe place for him to leave the toy overnight.
It's easy for a two-year-old's room to become overcrowded with toys. This can prohibit him from fully exploring particular toys. It sometimes helps young children to be presented with fewer choices. Rotate toys in and out of your child's playroom. That way he won't become overstimulated by the sight of so many different toys at once, and when the other toys reappear, they will be new again.
Some two-year-olds actually hoard toys because they aren't sure these will always be around. The concept of
You'll notice that the degree of self-centeredness in a two-year-old can actually extend to not wanting other children, even a friend, to play with one's toys. When a child's dislike of sharing is combined with the uncertainty as to whether an out-of-sight object remains around, you can understand why sometimes he might react very strongly when he can't have something he wants. You'll need to work through this seeming irrationality with your two-year-old, rather than chastising him for being unable to share and let go of his toys.