I'm a mathsy software developer, consequently logic is pretty important to me. Logic acts a vaccine against bad arguments and, as we're often exposed to ludicrous arguments, it's a pretty useful vaccine too.

For example we see these sorts of arguments when discussing climate change:

Some global warming is because of changes in the sun's output. The earth is warming. Therefore the warming is because of changes in the sun's output
Climate change can cause extreme weather events. There exists an extreme weather event. Therefore there is climate change.
If we can't get discussions past these sorts of syllogistic fallacies then how are we to get on to the more subtle, interesting and important debates? The interesting questions are hidden when we muddle "some" and "all".

I believe that most of us can see the errors inherent in the arguments above (although we might choose to ignore the errors if they confirm one of our existing biases), so why do these sorts of arguments exist? Internet comments and trolls. That's why.

Perhaps our web browsers should validate our text against valid syllogisms before allowing posting. This sounds like a hellish machine learning problem, but I look forward to the day when I have red wiggly underlines for spelling, green for grammar and (say) blue for whether the thing I'm writing actually makes logical sense!

Until then Stanford is running an introductory logic course on the Coursera MOOC at the moment.