As a group of mathematicians and physicists entered Wall Street since the 1980s, quantitative investment strategies have gradually become the fad. The successful icons of this move were Jim Simons' Renaissance Technologies and D.E. Shaw's eponymous quant fund. This shift led to the increasing desertion and skepticism toward qualitative strategies, a trend that closely aligns with what I observed during my tenure on Wall Street, intermingling with various institutions. Of all quant strategies, a widely favored and easy-to-implement framework is the multi-factor strategy. This approach simply extracts/mining various factors from a factor zoo and uses back testing to determine their efficacy and weights. However, in an era where factors are becoming crowded, multi-factor strategies have undou