The Reappearing/Disappearing Brush Tip
This one gets more people because it's a feature that acts like a bug. Has this ever happened to you? You're working in Photoshop, you're using the Brush tool (B), and everything seems fine. But a little later in your session, you get the Brush tool again, and it no longer displays the size of the currently selected brush tip. Instead, it displays a little crosshair cursor. So you go to the Preferences menu and choose Display & Cursors, and sure enough, you've got Normal Brush Tip chosen as your preference, but for some strange reason, it's not showing your brush size; it's showing that stupid crosshair. Here's the problem: Check your Caps Lock key. It's turned on, and turning it on changes your Brush cursor from displaying brush size to displaying the crosshair. This is actually a feature to be used when you need to see the precise center of your brush. The problem is it's assigned to the Caps Lock key, so every time you turn on Caps Lock when you're working with type, you just temporarily switched your Brush cursor (or any cursor for that matter). Does Adobe need to find a better key for this feature/bug? You betcha! Will it happen? Not as far as I know.