I haven't really been around Argentine's much but my first Boa is a Dumeril's, he's really defensive but very friendly if that makes sense. I mean, I open his cage and he will hiss and strike, if I set him down he'll coil back, hiss, and strike at me (was trying to get some pictures of him and almost got bit on the forehead). But as long as I grab him quickly and keep him in my hands he acts fine, he'll curl around my earlobe and side of my head...and imagine trying to get a reluctant snake off of your face and back into their cage. But I can't say he's aggressive since he's never came after anyone just doesn't seem to like seeing a larger creature hovering near or over him.