- If the whole point is that the transformation makes you vapid, but happy, why did the protagonist's father (who went through it) still keep his personality? Did the folks who created it "upgrade" it somehow? And how would they have done so if they were made blissfully stupid by the transformation?
- It's possible that the process might have been botched in his case, just like real-life surgeries occasionally go wrong.
- Another possibility is that what alters the mind of those who have the transformation isn't a full on lobotomy but something that an individual can overcome. Or just doesn't take on some minds. The brain is an amazing organ and can adapt through a lot. It's possible the father started out just as vapid as intended, and then slowly regained his mind/real self. Makes us hopeful for the protagonist....
- Alternatively, alternatively maybe the father got a type of transformation that only changed the body but he got to keep his mind due to his position or something. But his daughter got the FULL treatment meant for the lower masses so she'd settle down....
- Possibly, the Transformation only changes a person's body. But after noticing how some people were unhappy with the process (with the protagonist's father among them) which causes noticeable levels of dissent in society, they began to alter their personalities as well.
- The doctor specifically says in the end that, in the past, they had trouble with people not accepting the transformation, but they've improved the process since then so that doesn't happen.
Headscratchers / The Twilight Zone S 5 E 137 Number 12 Looks Just Like You