Ask ten dachshund people and you will hear the same shorthand: wires are the wild clowns, longhairs are the calm cuddlers, smooths are the stubborn originals somewhere in between.
There is a plausible mechanism. The longhair coat likely arrived via spaniel crosses and the wire via terrier crosses, and temperament genes could have travelled alongside the coat genes. A century of separate breeding within each variety would preserve any such differences.
The confound is the owner
The bigger effect is probably self-selection. People who want a lively, gamey dog gravitate to wires; people who want a decorative lap dog choose longhairs; breeders then select their lines toward what their buyers ask for. Over time the reputation becomes partly self-fulfilling.
The practical takeaway is unchanged: coat predicts grooming workload reliably and predicts personality only loosely. If temperament matters to you, evaluate the individual puppy and its parents, not the jacket.
