Aesthetics or fun needs to be secondary to usability. If making something "fun" comes at the cost of making the design less usable, it should be avoided.
Obviously companies need to define their own image in design, but that is not an excuse for bad design.
I agree, and one issue for developers and designers alike is that often, it’s more fun to make a UI fun than it is to make it work really really well.
But that doesn’t mean we should lose sight of fun completely, which I think in many places we have!