You're conflating a couple of things here. It's true that users don't like change - and for good reason; messing with UI invalidates their acquired experience, and even if you know you've changed only one small thing, they don't know that. It quite naturally stresses people out.
Two, I'll grant you that you sometimes have to use a custom control, because web moves forward faster than browsers, and so you can't count on a browser-level or OS-level calendar widget being available. But then the issue is, how do you do it. Can the user type in the date directly into your custom field? Is the calendar widget operable by keyboard? Such functionality doesn't interfere with first-time use, but is important to enable users to develop mastery.
A lot of my dissatisfaction with modern UI/UX trends comes from that last point: very low ceiling for mastery. Power users aren't born, they're made. And they aren't made in school, but through repeated use that makes them seek out ways to alleviate their frustrations. A lot of software is being used hours a day, day in, day out by people in offices. Users of such software will be naturally driven towards improving efficiency of their work (if only to have more time to burn watching cat photos). If an application doesn't provide for such improvements, it wastes the time of everyone who's forced to interact with it regularly.
Two, I'll grant you that you sometimes have to use a custom control, because web moves forward faster than browsers, and so you can't count on a browser-level or OS-level calendar widget being available. But then the issue is, how do you do it. Can the user type in the date directly into your custom field? Is the calendar widget operable by keyboard? Such functionality doesn't interfere with first-time use, but is important to enable users to develop mastery.
A lot of my dissatisfaction with modern UI/UX trends comes from that last point: very low ceiling for mastery. Power users aren't born, they're made. And they aren't made in school, but through repeated use that makes them seek out ways to alleviate their frustrations. A lot of software is being used hours a day, day in, day out by people in offices. Users of such software will be naturally driven towards improving efficiency of their work (if only to have more time to burn watching cat photos). If an application doesn't provide for such improvements, it wastes the time of everyone who's forced to interact with it regularly.