It depends on the type of reptile. Many turtles and tortoises are very friendly, same with certain lizards. I will say, I've heard iguana can be nasty. Some snakes are also very good with people. I'd recommend a leopard gecko or crested gecko for a lizard. Corn snakes or ball pythons usually make good starter snakes, just know they CAN get very big.
They are wild animals. They might not bit you if you don't threaten them or if you are bigger than they can eat but by nature they don't have the social understanding that most mammals have. That is because they mostly live alone after they get out of eggs. They lack family dynamics by nature, as opposed to mammals.
Ofcourse! If you treat them right :) I have a ball python (snake) and she is so sweet and has never bitten anyone. I love her so much and i handle her almost everyday. I also have a bearded dragon (lizard) and he is 19 inches long and so sweet and calm! He loves to sit on my shoulder :)