Exception to the rule, you can take a sharp negative and create a unique pictorial effect with a simple lens at the enlarger.

I have two shots, 4x5 prints, from a Ricohflex TLR where I printed using a simple lens and the mood is awesome. Note, I used crisp borders, and no edge markings for the prints, so there was no telltale sign of lousy optics. I always blamed the camera for the soft edges, until I found the original negatives which are sharp as a tack (relatively considering the character of Ricohflex optics).