You can always force close the app and that'll make it reset itself, and sometimes it'll fix problems with misbehaving apps. Now if you want to disable it all together just hit the disable button and click yes, so that way the app stops working all together until you restore the app to work again.
Most built in apps can be disabled by opening your app drawer and long pressing on the app icon, and then dragging the icon to where it says "app info" at the top of the screen. Depending on which app you may or may not be able to disable it. Note that disabling the app will make it as if the app is no longer installed. In order to restore a disabled app just go to settings/apps/disabled and you can re enable them from there.