The word 'surprising' appears 12 times more frequently in the natural sciences than in standard English and 1.3 times more frequently than in social sciences, arts and humanities. The word 'unexpected' appears 39 times and 2.2 times more frequently in the natural sciences than, respectively, in standard English and in non-science academicHe attributes this phenomenon to a desire for publicity:
Although natural phenomena can indeed sometimes be surprising if they are against our expectations, being 'surprising' is not an inherent quality of nature. Does scientists' use of this term in their publications truly represent genuine surprise at their results? One might think that academic machismo or realism would cause scientists to downplay their surprise, but, on the other hand, overstating the level of astonishment may occur when striving for media attention.Ewan, over at Complex Medium, agrees that publicity is probably the reason for the frequent use of "surprising" and "unexpected." Tara, at Aetiology, does not - although she does wonder if the words in question might be overused.
Personally, I think that being surprising is pretty much an inevitable consequence of our current level of understanding of nature. We've learned enough to know that there is a hell of a lot that we don't know, and we're continuing to develop tools that let us poke a little farther into our ignorance. If we weren't being surprised on a regular basis, it would imply that we actually have a pretty good handle on the nature of nature - and that really would surprise me. That's one of the reasons for the frequent use of the term.
Another reason that we scientists use those words so often is that "surprising" and "unexpected" is where we live. It's where we do business. It's what we are looking for. We are trying to answer questions that we don't already know the answers to. If you're not being surprised on a regular basis, you're probably not doing real science.