Jefferson Graham, USA TODAY
LOS ANGELES - When the week began, Apple trumpeted dizzying adoption of its new iOS 7 mobile operating system, with a whopping 200 million downloads.
But users aren't totally happy.
In fact, some are a little queasy.
Apple customers have taken to Apple message boards and Twitter to complain that the flashy graphics in the new operating system for the iPhone, iPad and iPod Touch are making them light-headed.
HOW TO: What you can - and can't - do to adjust visual effects in iOS 7
The iOS 7 update "makes me dizzy with the constant movement," writes John Isom of Huntsville, Ala., on Twitter.
With the new update, navigation between screens produces an effect quite different from the static swipe of before. Now the icons zoom in, like opening credits of a science-fiction movie. Additionally, when you open an app, it feels like it is "exploding" toward you, Isom says.
Elliott Lockwood of Omaha writes for the most part he likes the new OS but that the animations "are a little long and make me sick after awhile."
The effects are so intense Elizabeth Kerr kept her 12-year-old son Mitchell home from school on Friday.
"He gets motion sickness on road trips," says the Chicago-area resident. "The phone is making him dizzy."
Her reaction: "It's disappointing. It's too bad that we had to go so far with animation that it has an ill effect on people."
It's a fact of life in consumer technology that when change comes to familiar services, a loud group complains that they missed the old ways.
It's happened time and time again to Facebook and Google. And each Apple update usually produces a loud discussion. Remember "Antenna-gate" when the iPhone 4 was released and folks complained about missed calls? Or the howl (and more real) response to the release of Apple Maps in 2012, when Apple ditched Google Maps in its iOS 6 update and replaced it with its own, inferior service that caused Apple management to publicly apologize?
Apple didn't respond to requests for comment about the visual effects in iOS 7.
Analyst Greg Sterling of Sterling Market Intelligence believes the online comments are "an over-reaction" but that if it really develops into a problem, "Apple will fix it."
His advice to consumers who haven't downloaded the update yet: "Try it on a friend's device first. If you like it, then download it."