Two Sims Don't Have A Hobby Interest?

I barely recall this was a problem for some Sims never picking their preferred hobby. And ninety percent of the Sims I created for hood all wound up with Music and Dance as the one they prefer. :s I must have picked too many of the same personality traits or something. I thought there used to be an object mod to change their hobby (a vase or painting or something) and how do I get a mother and her adult son to finally pick a hobby? ETA: They have tried them all. :/