Using a wide aperture gives shallow DOF. The design of the lens determines the character of the out-of-focus areas ('OOFAs'). These are two different things. Since most all 50s for 35mm are double-Gauss designs, their OOFAs will be similar; differences will be due to the optimisation chosen as well as the degree of "retrofocality" of the lens in question. Lastly the shape of the aperture will determine the shape of out-of-focus highlights.
Originally Posted by Thomas Bertilsson
Usually when I hear or read someone babbling mindlessly about the "great bokeh" their lens has I translate it thusly:"I can't take a decent picture to save my life, so I read some nonsense on the internet and bought this lens which I'm now making an a$$ of myself with".
I learned that a wide aperture was useful to separate the subject from it's surroundings/background, as well as taking photos in poor light. But that was a long time ago, much has changed in 40 years.