Crested geckos are often separated from the other animals of the same species in pet stores. That is not an accident. Crested geckos are actually solitary animals, who prefer to be on their own, except when it is mating season. They are certainly not social animals like you would expect with a dog or cat. However, the unsociability of crested geckos does not make them bad pets, at all! They are, in fact, the exact opposite, for that reason.
If you want to have a pet that you can handle, then a crestie is great for you. Providing that you handle them gently. Furthermore, you can devote all of your attention to the single pet, and not get distracted by the other one.
If you do decide that you want to have more than one, however, you will need to think again. Female crested geckos can usually live together without any problems, but when you start to mix males with each other, or males and females, you are going to have a lot of fights and stress to deal with. So, make sure to get a female if you think you may want more than one in the future!