Kakashi is a mutt of all emotions, if you don't mind the pun. The first impression ever gets of Kakashi is a inattentive jounin who must have made that far by a fluke. This, of course, is demonstrated when Naruto puts a chalk eraser on the door so when Kakashi walked in he it would fall on him. That's what he gets for being late, n'est-ce pas? Then, as many things do, the Kakashi persona changed to an evil person. Not really evil, but he told his little team not to eat breakfast, and of course they didn't so they were hungry all day.

One quickly learns through his test that he is very fond of teamwork, and won't pass anyone who doesn't exihibit it. Of course, then evil Kakashi changes to sweet Kakashi, then to sweet Kakashi "you pass!" then to angsty Kakashi. Yes, Kakashi is an angsty little bugger.

One begins to learn throughout the series how much Kakashi is really like Sasuke, or the other way around. The two both grew up in a time of war, and have experienced a great deal of pain. Kakashi, however, keeps his secrets fairly well, so we'll just have to watch Sasuke to see little glimpses into Kakashi's past.

Now, Kakashi is by far one of the strongest Jounin (he'll be Hokage some day, i swear! He already knows more than 1,000 jutsus which is on of the prerequisites!), but he never really seems arrogant. He is, in most times, confident if even that. He displays the correct amount of cautiousness in all situations (which can be seen when dealing with Zabazu) and he calmly thinks all things through, such as "Who will the enemy attack? Who is in danger? What is the guy looking for, and what means will he go through to acheive it?" all through the midst of a fight that scares even Sasuke. Scaredy cat Sasuke.

In general, Kakashi is light hearted, laid back, and deadly serious at pretty much all times. The serious changes from time to time. It's been my experience when reading and watching the series that he starts with a joke and gradually comes to a grave diatribe. Take for instance the fight with Iruka, or everytime he meets his team. Joke first (mainly about being late) then serious business, then he disappears. Gotta love Kakashi!