I'm not sure I agree with that.
Personality can change through growth, trauma, as a result of hormones or of any life-changing experience
The person who is scared witless and still does a brave act is far braver than the person who isn't frightened at all
A person's sense of humour will change depending on how they see themselves such as the result of experience such as results from formative incidents, reading or age
While it is indeed possible to mimic aspects of someone's character, 99.9% of the time other people will feel something wrong when they see this done, while if a person genuinely wants to change aspects of their own character (their personality) not only can they often do so, but others are less likely to feel 'wrong'
Finally, for most people I doubt very much the choice to read will be a question of basic character attributes. Far more likely it'll be because they do or don't have time, because they do or don't accidentally (or deliberately) come across your post or other fairly superficial reason..
Have fun!