Crocodiles, along with sharks, are regarded with a good deal of trepidation and outright hostility by the human race - particularly by people who have never been within a continent's width of them.
Also, like the shark, they sussed several million years ago that if you can grow to over 20 feet in length, have really big teeth, and a natural predisposition to snack on passing wildebeest/cattle/dumb tourists, then the whole evolution thing is really a waste of time and effort. Yes, these largely tropical creatures have stayed pretty much as they are (well, maybe not pretty) since before our ancestors made it out of the trees. In an age where we are told that businesses, society and individuals must adapt or die, it is nice to have living proof that this is absolute rubbish.
This does not mean that sharing your beach or river with one is a sensible move. While some species1 are mostly harmless, others2 are not. In these enlightened times, you may regard them as a noble and fascinating reminder of the natural history of our planet. However, they are more than likely to regard you as lunch. Or more likely next week's lunch, as they tend to let their snacks decay a bit underwater before eating to ease the digestive process.
Official guidance on avoiding unpleasant encounters makes sensible suggestions, such as not swimming where there are crocs, not collecting water from the same place in a river every day, and being very careful when fording rivers.
If you do get into close quarters with a crocodile, unofficial guidance, provided by a nice chap at the Manly Aquarium in New South Wales, Australia, is to run in zig-zags like a rabbit. Apparently crocs don't corner very well, and are too dumb to head you off by running in a straight line. If you end up very close, similarly insane advice is to sit on the croc just behind the head where the jaws can't reach you. How you get out of this situation is not clear.