So, what is my WTF moment of the day? Graphics artists who turn up their nose to certain technologies as being "inferior" and "not having enough fidelity" when sticking to PDF as "the one true format that does everything with maximum precision and is just good enough for our job".
Example: I know there are minute differences between Arial and Helvetica fonts. Can anyone but a graphics artist who works with them on a daily basis see them? Nope. Can we - for all practical applications like writing receipts and creating dynamic webpages - ignore those differences? In my book, yes. They are close enough to work as substitutes. But graphics designers blow a fuse at the mere suggestion.
And yet... PDF... I am currently digging into the specifics of the format and - as usual when learning these things - writing my own library to handle reading/writing it. I can write text (with one standard font so far) and draw lines and fill rectangles with a solid color (either RGB or Grey) just fine. Now I wondered: Hey, let's do a circle next! Just to find out: PDF does NOT have a circle drawing primitive! It just can't be done! It only has lines and cubic Bézier curves. Which can only approximate a circle, but not quite hit it.
So here's where I cannot listen to people who gripe about some obscure line cap difference in Arial vs. Helvetica anymore, when all circles that they ever drew where closer related to eggs than spheres.
Disclaimer: I am not talking about different fonts like serif or sans-serif fonts, condensed or wide, bold or regular or even custom kerning or leading. Just those little glyph differences that are just about as prominent in normal text as the difference between a circle and a four-curve approximation.
That is also the reason that Illustrator (and some other graphical applications) will draw a circle that is actually a pre-defined path... because when it boils down: PDF can ONLY do cubic Bézeirs: Even straight lines are Bézeirs with the control points happening to be the same as the origins.