I came to APL slowly, originally motivated by some combination of fascination with the syntax and desire to break into the financial sector.

However, what got me to invest in earnest study was hitting today beginner's wall and realizing that I had no idea what Iverson was on about with his design principles.

APL is really different these days, as far as I hear. Dyalog APL is the only vendor actively working on the language these days, and the old hats tell me that things like dfns, trains, and various operators make modern APL quite different from APL even just 15 years ago.