Your cham doesn't hate you. It thinks you are either a predator or an intruder. Baby chams haven't started asserting themselves as territorial animals. As they get older they develop more confidence and will resent you (a big weird colored potential predator) getting in their space. The best way to keep a cham tolerating you is to hand feed it favorite treats. Chams are also individuals. Some are more social and tolerant of handling than others. It isn't something you can really change. If you have to remove the cham to clean etc. you can coax it onto a loose branch and lift out the whole branch. Don't pick it up by the body. Let it climb onto your hand instead, move slowly, or if you really have problems turn the lights out for 5 minutes to create a fake night. The cham will slow down, cool off, and not be as reactive.