As a guy who has dove with both, I can tell you I was much more wary of the crocs than the sharks.. and, yes, sharks - if you see them before they attack you - do send you specific signals that tell you to back off or you're gonna get nailed.. I look for those signals whenever I go chasing after sharks with the go pro.. But the crocs just sit there and do nothing.. then you don't see them, then you're in a death roll..
The firs time I jumped in the water with sharks circling the boat was a trip.. but I got used to them quickly.. The first time I jumped into the water with two crocs in the water, I was nervous and looked behind me the whole dive.. it was just me, my wife, and the dive guide.. the dive guide at first didn't want to get in.. I was about to jump in the water and he held his hand out to stop me.. he didn't speak English (this was in Mexico on a cave dive) but pointed to his eyes, then pointed to a location in the water about 20 feet from us.. it was then I saw two sets of eyes sticking out above the water line.. Eventually we jumped in, but I was never comfortable with two crocs in the same body of water...
Friendship is like peeing your pants.. Everybody can see it, but only you can feel the warmth..