What has surprised me the most recently is reading this THINK document about the huge effects that self-improvement can have on one's ability to change the world for the better.
I was also surprised to learn that 25% of the philosophers that responded to Brian Leiter's 'Philosophers, Eating, Ethics' poll said they were vegetarian and an additional 8% said they were vegan. In other words, a whopping one third of respondents reported being either vegans or vegetarians. The proportion of vegetarians in this sample is about eight times larger than that of the general American population; the proportion of vegans is 10-20 times larger.
I don't think there a valid reason to assume that all people who responded to Brian Leiter's internet poll are philosophers.
There a good chance that the poll isn't representative of the general population of philosophers.
Information that surprises you is interesting as it exposes where you have been miscalibrated, and allows you to correct for that.
I suspect the users of LessWrong have fairly similar beliefs, so it is probable that information that has surprised you would surprise others here, so it would be useful for them if you shared them.
Example: In a discussion with a friend recently I realised I had massively miscalibrated on the percentage of the UK population who shared my beliefs on certain subjects, in general the population was far more conservative than I had expected.
In retrospect I was assuming my own personal experience was more representative than it was, even when attempting to correct for that.