The funny thing is I quit hacking because it was easy, mostly unimaginative, and repetitive. The high-assurance systems and security fields were much more interesting. Especially the CompSci work. These are about straight-up engineering systems or security methods in ways that they'll always work given a specific threat model. Lots of good stuff came out of that field with things occasionally breaking in new ways due to immaturity of computing discipline. Yet, certain things are well understood to the point that 60's-80's era methods get 80-90% of the job done. Still unknown to most INFOSEC people in mainstream. So, don't worry when they act cocky. :)

Anyway, the market rejected that to maximize profit with buggy software and consumers wanted unnecessary complexity at a rapid pace in every aspect of computing. So, I typically recommend medium assurance solutions these days. Safe-by-default languages, interface checks (esp Design-by-Contract), usage-based testing to keep users happy, fuzz-testing to find lack of input validation, static/dynamic analysis tools, good architecture, good middleware, OS with few 0-days, and so on. These cover you mostly.

What type of apps do you build on what platforms?

EDIT to add: Link below has a link and description to lots of defense techniques that aren't boring at all. What do you think on that?

https://news.ycombinator.com/item?id=11596646