Have you ever struggled to keep up with a boss who constantly switches gears? You're going along, managing your workload as best you can, when suddenly your boss says "Hey! Let's try [XYZ new idea]!
"You feel obligated to say yes (because it's your boss, and you're a reliable, responsible employee)...but your boss doesn't seem to understand how much time and effort you're spending on your current projects. You really can't handle this shifting of goalposts right now.
How do you communicate this to your boss? How do you scope a marketing project, get your boss to respect the workload involved...and save your own sanity?