6. Playing "Hide the Button"
You can make anything into a button in Flash.
Anything.
A single period, a blank area, the very top curve of the letter P. This can be fun if you're designing a treasure-hunt-style game. This can be immensely aggravating if you're setting up navigation through your Flash movie and your viewers are expected to guess what might and might not be a button, and where it goes. People will get frustrated and leave before finding anything of use, and most of them won't find the concept as clever as you did.
7. In-and-Out Zooms
Dizzying, much? You can use Flash to zoom your scene in and out rapidly Wayne-and-Garth style, and I've seen it done many times.
With that said, don't.
Enough said.
8. Pop-Up Windows
You'd be surprised at the number of major websites--MSN.com is the most prominent example that comes to mind--that use Flash to create a sort of "layered" version of popup windows that open in the same window, splashed on top of the content that you're trying to view, instead of in a new browser window. This is a very clever way to get around your typical popup blockers, but also a very rude way to force advertisements and content on people who use those popup blockers for a reason and don't appreciate being thwarted in their attempts to avoid persistent "buy me buy me buy me" marketing.
On the positive side, most of the major websites do include a little button that lets you close the advertisement. A great many smaller ones, however, don't--and force you to sit through the ads until they play out to their conclusion and then close themselves. Don't do this.
9. Pop-Under Windows
What's the difference between a pop-up and a pop-under? A pop-under actually opens beneath your regular content--but it's still there, and twice as persistent as a popup, and less likely to have an option to go away. Using Flash to stuff these into your movie or site is going to tick quite a few people off and cause them to give up on viewing your content.
10. "Sticky" Mouse-Trailing Objects
I'll admit, mouse-cursor trails can be cute if they're done well. If they're small, unobtrusive, or clever, then I don't mind them. If they're large and invasive, however, they're enough to make me start muttering words best not repeated here. They can be visually distracting, and can get in the way of trying to browse through content.
Even worse is the "sticky" object that attaches to your mouse pointer the second that you enter the area of the Flash scene, and follows it around, making it difficult to see what you're clicking on and hard to follow the content beneath your mouse. The drag and drop functions available through ActionScripting are good for many things. This is not one of them.
