Beware of Snakes.
Visitors to Australia are convinced that they are at risk from deadly spiders, snakes, jelly fish and insects (unspecified). In fact, I would be genuinely surprised if even 50% of visitors see any of these creatures. While we were in Australia we saw one snake (and we were in the car so entirely safe), one spider I'd be a bit wary of (not deadly, but has a bad reputation), no problematic jellies and the deadliest insects we saw were Honey Bees, which aren't even native.
This pavement warning, by the way, is at a layby on Lake George, on the road between Sydney and Canberra. I have no trouble believing that there are some very venomous snakes in the area, but I bet very few people see them. We certainly didn't.