The insurgent investor Nelson Obus explains how listening in on his dad’s basement meetings put him on the road to investing, then later, Lazard banking and finally activism. In a wide-ranging conversation, Obus, 71, explains what kind of companies he finds attractive and why this year his 25-year-old fund opposed another activist investor’s director battle. He also gave us an inside look at how he shook up the board of Omega Protein, an “entrenched” company that was diversifying in all the wrong ways until Wynnefield showed up.