Why is it so common to join extremes without watching a guide first?

[Vahlnir]

Mixed feelings here.

I mean, I've watched numerous guides throughout my (limited) time playing FFXIV. Sadly, I don't generally remember much of what I saw in the guide when I'm 'on the spot'. I guess I learn more through actually doing - although still make daft mistakes even then.

Guides only provide a rough draft of what to expect. Actually performing the required mechanics is another thing entirely. So yeah, guides help, and I would always suggest watching one for an Extreme or Savage boss, but the true learning comes from actively doing a fight. You can't really account for human error in a guide either, and there's plenty of that to go around. It is also extremely difficult to get every party member on the same page because everyone learns at a different pace.