I believe not. Anything that excites you brings with it a certain fear, or vice versa. Why is that? Propably because it is only the out-of-ordinary events or things that excite one and by definition these being new bring with them a certain fear of the unknown. It is a natural human reaction. The only difference in people is the varying amounts of each when faced with the same situation. I do not bungee jump as my fear overshadows the excitement that I have for it. In Arthi's case I believe they are 50-50 and she is as much inclined to do it for its excitement as she is scared. And there are tons of people for whom the excitement value is much greater than the fear.
Looking at it another one - we could propably say that fear excites. I am sure there is some biological explanation for this - but being one from the I-hate-biology camp, this is what I gather from my experiences and musing about them.