Some can and some cant. Reptiles have not been bred for being gentle, although some heavily captive bred species, like corn snakes, seem to be much more calmer than wild caught specimens.
Some species are more easy to get used to than others and other species wont be shy and may even eat from your hand but wont allow you to touch them. Other species will allow you to touch them in return for food. If you are buying a reptile and want it to be tame, consider buying an animal that is calm and friendly.