For me it was Delphi. This was in the nineties and it was a beautiful language paired with a UI editor in a time when that didn't exist (there was only VB (ugh)

For me it was Delphi. This was in the nineties and it was a beautiful language paired with a UI editor in a time when that didn't exist (there was only VB (ugh) or MFC, if that really counts as a UI designer.) It had a huge influence on languages, especially C#, which feels like Delphi-with-braces to many Delphi programmers. For me as a teenager, it was when I "got" OO programming and set me off on a programming career, which led to many adventures (sailing, natural disasters, etc.) I came back to it quite recently and it's advanced a lot, although I use its C++ sister product, C++Builder, which pairs the same UI tech with C++, a trick that is hard to pull off (Qt manages it, through many clever C++ tricks; C++Builder does it through a couple of neat language extensions which I feel is cleaner overall. I really like it. This year I started working at the company making it, so full disclosure there, but I work there because I like the tech so much.)