There are many who seem shocked with the rapidity that some transgender and nonbinary people will transition. To them, it seems like overnight someone will go from coming out to a whole new visible presence.
Physical changes will be sought in what seems like a blink of the eye. As a result, people can feel that their enby or trans friend is making a rash decision, as if they just one day decided to transition and are going full bore without clearly thinking through the ramifications of these changes.
This attitude is at the heart of things like the largely discredited Rapid Onset Gender Dysphoria, or ROGD, theory that claims transition is some fad that people undertake shortly after first hearing about transgender people on the internet.