From making a fool out of pompous royalty to pulling one over on the common man, Manannan seems to enjoy his role as a trickster the most. Sometimes this guise leads into that of the sage, when he reveals the wisdom behind his tomfoolery.
The trickster is Manannan's most dominate guise, although it never seems to be a force of destructiveness as with tricksters in other pantheons. The few myths where Manannan's humor goes over the top always end with him setting things right again. In real life his mirth is always just under the surface, and his jokes can often pack an element of surprise where the punch line doesn't become clear until much later.