Elephants are fine unless you bother them, or if they think you are going to. Even then, they give you plenty of body-language before doing anything serious about it - ear-display, head-up, trumpeting, staring, that sort of thing. Even someone who hasn't seen that before can easily tell when they are getting annoyed. The final warning is a mock charge, which believe me is scary.
The only "rogue" elephants are those that have been badly mistreated or attacked by man. You occasionally come across them, and you can tell pretty quickly. Maybe their own relatives have been killed by poachers, or someone stuck a spear in their ***, or something like that. When these see you, they come at you and just keep coming. No mock-charge with them, you can tell straight away that they really mean it. You have to get out of there, FAST!
@ fnmag: Flat dogs / handbags (crocs) are neither mean nor unpleasant. They will just eat you if you go in the water or too near them. There's no malice in it - you are just food. Although the species is millions of years old, the last of the dinosaurs, they are highly intelligent, and very crafty.
Hippos are bad-tempered and mean. They look clumsy and lumbering, but they are FAST. They have huge jaws, and will bite a canoe in half if it goes too near them. They kill a lot of people. Don't get between a hippo and where it wants to go. A guy I know moored his fishing boat on the river bank and a hippo just decided to sink it, because it was in its way. He had to dive down 12 ft to get it back (very risky) then strip down the engine and all the other stuff to get it working again. All because the boat was where the hippo wanted to get out of the water.