|When your boss gives you little projects that cause delays in your regular work, it is time for a little chat.|
Such a discussion is not a time to complain about the workload or the assignments themselves. Rather, it is time to discuss priorities and expectations, and there are a couple of approaches that may work.
A reactive approach is to wait until he gives you one of these assignments, and then tell him that it is going to cause other work to be delayed. Give him the specifics and then ask what he wants you to do.
A proactive approach is for you to meet with him for the sole purpose of discussing these so-called little assignments. Let him know that they are causing some serious delays, and then ask him to clarify the priorities for you.
Some managers keep adding little projects to their employees' workload until their employees say the little word, "No!" Doing so will not indicate that you are lazy. If you were, your manager would not be giving you the projects in the first place. But, if you don't say anything, the projects will keep on coming. Your boss understands that your limit is going to be reached at some point. And, that's the point right now.