Actually, EShy, we're dead serious. Unless you've got apps starting up and placing themselves in the foreground, let them be. Just because they're in the memory, doesn't mean that they are consuming enough resources to be noticible. If you use an app such as OSmonitor, you'll see that they've aren't using any CPU cycles while sitting there idle. And the way that Android handles memory is not the same as your PC. If more memory is called for, it will begin to kill off apps or processes that are not being used right away.
Plus, a lot of those apps that start automatically, aren't doing it just to bug you. They're doing it because their processes were called upon by another app or phone function. When you kill them, most of the time they will have to open themselves back up, and that DOES take system resources.
Now, if you were just using an app or game, and it didn't close properly you may wish to kill it manually before it runs its course over time. But 95% of apps that start up by themselves are not going to hurt anything.
