One of the things you do when teaching object-oriented programming (especially when you learned to program in the structured programming era) is spend time thinking about how programming paradigms come and go and how much of the impetus to change has been restricting what programmers can easily do so that they have less leeway to get into trouble (hopefully meaning fewer bugs). Then my colleague Daniel Lemire goes and questions the utility of debuggers, and I wonder if all of these linguistic and developmental tools merely serve to make software developers lazy. Why bother to really understand your code (for instance, trace it by hand) when you can scan through it while it runs? Who cares how inefficient language X is; machines are fast!
This is my pet peeve: software manufacturers are burning my machine cycles, which I paid for with my hard-earned money, to reduce their effort in producing quality code. If you don't believe it, go to The Computer Shootout Benchmarks and compare the trendiest, most "modern" languages' performance with C. The best you'll find is C++, which looks to be about 30% slower than C in general. C#/Mono? C is 2-70 times faster. Java? C is 2-66 times faster. And C is hundreds of times faster than Ruby et al.
What do I get for all these extra cycles? The only thing I can see that is of value to me is platform independence. Is it worth buying a machine twice as fast as I might otherwise need? Maybe. Four times as fast? I'm not so sure. Seventy times as fast? I'm sorry. Where are all those extra cycles going? To absolving companies from the need to discipline their development processes. In other words, I'm paying more money for a computer so companies don't need to pay as much attention to the fine details of product quality.
Disclaimer: The above doesn't apply to computation-intensive applications, for which the more cycles the merrier. I don't play video games, but I do write simulation code. But should you really need a multi-gigahertz machine to write a letter? I wrote a 200-page dissertation, with drawings, graphs, and all sorts of typeset math, on a Mac SE (using LATEX).