COBOL

The business computing language since the 1950s.  A large percentage of banks and the US government still use COBOL, because massive batch processing, money, reliability, and most important, easy to learn. COBOL was written for C students. Robust, fogiving, a Soviet tank of  a language, you could write hideous code and the computer would still work. 

There's other reasons for using inefficient and antiquated technology. Software, unlike hardware, gets better over time as bugs are stamped out. Utilizing a new system means starting all over. Why do that? Do what Nature does and build kluge upon kluge. 

I myself wrote programs in COBOL, and I got two insights working in IT.

1) Clever is the enemy of Smart. Even Stupid has a problem with Clever. Clever solutions are contingent and often accidental, not replicable. Smart solutions, once they work, work until they don't. Stupid solutions resolve quickly one way or the other. Clever can be Stupid posing as Smart.

2) The world is always making a better idiot. There is no such thing as idiot proof. See 1).

Working at one company I noticed they didn't have a lot of common modules programs could call, like an app, and get a result. You know, basic stuff like day of the week, number of days between dates, code that was needlessly replicated. These were installed as what were called black boxes and used. One day, the day of the week subroutine went kablooey. It was quickly determined that a newbie was curious about the black box, looked at the code, decided it didn't look right, and changed it.  

3) KISS Keep It Simple, Stupid.

Back in corporate days I once reviewed a COBOL program for Accounting a bright lad had wrote. I went through the code and complimented him on the elegance and brilliant little subrouines he had written in this concert of a program. 

"We can't use it". "What?" "Can't use it." "You just said it was a beautiful program" "Yes, and this program has to be maintained in the future by people not quite so bright as you and I. Sorry. Turn it into a brute force double sort match". By this time I had realized that all these smart programmers were C students who thought they wre getting straight As.

Do I care? Nah. I may look like a slacker, but I work until I have enough money to not work. I not work, until I run out of money and have to work again. If this were the 19th century, you would say I won and lost fortunes. But I have enough slack saved up to tranport me clear to Venus.