My ZorroThat said, you have to commit to look after them properly. As many know, I'm against buying iguanas in shops as there are far too many being abandoned, waiting in rescue centres and even on fora where people want/need to get rid of them. It would be my wish to give all those looking for a home a place to stay until they die and ban shops from selling them. Rather have private breeders who know what they're doing and who are able to educate or guide the new owner.
Of course you're more likely to get an iguana with issues if it's older and went through several hands already. I've tamed one very aggressive alpha-male once. He was unknowingly mistreated and charged at me at any given time. Together with my vet, I managed to calm him down. Unfortunately, I was so allergic to him, I had no choice but to give him away. I still haven't forgiven me, but it was the only option since my female didn't get along with him at all and was so stressed out, she could've died. Yes, they can die due to stress. One might think they are robust - and they are, but on the other hand, they are rather sensitive to changes, mood swings, etc.
They have sharp teeth that rip you flesh open.
My big boy who's been with me for three years now has been super friendly and tame when I got him. Then he reached maturity and changed from one day to another. Since then, I've got severe difficulties when he's in mating season. He's aggressive, he's charging at me, he brought me to A&E and what's more distressing: he's hurting himself. Jumping against the glass, furious tail whipping, biting, etc. My arms look like I've failed a few suicides, his rather sharp claws leave bloody scratches.
You might now think: Oh, I'm getting a female, then. Well, you better put some money aside, because they are prone to have difficulties during breeding season, too. Mine laid eggs every year, even without having a male to mate with (apart from 2.5 years), and we went to the vet every single year to get the eggs out of her. Though she laid about 35 eggs, there were always some that wouldn't come out. If they remain inside, it can lead to an infection and finally death. After a few years with the same trouble, I had her sterilised. The insurance excludes breeding season-related claims, so it's a long and painful process for the animal and an expensive one for the owner.
Females might be friendlier in general, but I've heard from other iguana owner who get bitten, whipped and hissed at. I was rather lucky to have this enormously friendly and cuddly animal. And yes, she often would crawl onto my lap and fall asleep.
When I mentioned aggression issues to people I got the strangest suggestions and to be frank, I was shocked. The suggestions ranged from putting blue tack onto this claws, filing his teeth, pulling the claws, cooling down the temperature in his vivarium, not feeding him, finding him a female to 'mate' (he'd probably just bite her to death) or even to give him away. That's when I'm really really glad he's with me. Of course I'm annoyed with him once in a while, but more because I'm worried about him. It's not his fault, he's a wild animal who didn't choose to live with me, I chose him. I have to accept, that, for a longer period (can last up to three months) I have to be extra careful and try to handle him as little as possible, first to not stress him and second it's safer for me. If you want to see how hefty bites can be, google iguana bites, there's a very graphic video from some fingertips that came off (ouch), even I couldn't watch it and I had my fair share of injuries.
I've heard a lot of people saying, "Yes it's just because the iguana doesn't like their owner." I cannot agree with this statement. I've had three, all three had a complete different personality. My first iguana was the friendliest and exceptional iguana in the world, adored by everyone. The first male, I described above, he was mistreated and didn't trust, but I got him there, though he was also an alpha male and attacked the next owner. Zorro is by far the most aggressive I've ever seen during mating season. Though he's never really tame, there are times when he is up for a good head rub, but I need to be on alert at all times, one wrong move and the finger's off.
My female, she passed away after a hefty operation three year ago.
Cuddly iguanas are rare, aggressive ones are more the norm. So don't be fooled by anything others tell you, especially not shop assistants. Males become very strong and big, Zorro weighs 11pounds and is about 4'9". I have my difficulties handling him alone. Since he's bumped his nose a lot, I'm giving him painkillers daily (oral) and injections of antibiotics every three days. Examining him isn't easy since he won't sit still, either, he's head bobbing or he's moving around. As soon as I get closer and try to go near his snout, he'll bite wildly. I'm trying, though, I need to keep an eye on his snout.
I hope I've opened your eyes a little bit more about keeping these wonderful creatures. All I'm trying is to raise awareness so that less people buy them or if they do, that they commit and don't get rid of them because they become difficult. They are animals who depend on your TLC.