I first read this when I was 18, and it's just as exciting to read now as a jaded curmudgeon. As two points of reflection:
1. Wow, SI texts read so much more fluidly now that I have a grasp on the whole canon. I imagine about 80% of the references went over younger-me's head: I had no grasp of Hegel, Marx, etc., tenuous understanding of Algeria, Vietnam, the Paris Commune, and certainly no methodology for reading with dialectical rigor (that's tongue in cheek, FYI). These roughly 500 pages went by with ease, which probably says quite a bit about how I've "heard it all before" BUT ALSO I now have life experiences that echo and reflect the same issues. History repeats, alas.
2. The things I find exciting are noticeably different, yet still the same, due to being on the opposite side of the threshold. As a teenager, the SI presented me with the idea that I could live life the way I wanted, with a nearly-infinite number of paths I could take from that point forward. The adventurism (AKA "lifestylism") could be the force that takes me day by day into the unknown. Fast forward to the present day, and of course that didn't play out the way it could have. I'm more tied to my habits (work, home life, etc.) but still have that yearning to explore in my time off (yes, yes, the critique of leisure time, I'm aware). Let's be real though, none of the SI actually lived this way either, yet some of those they denounced did (a certain urban cowboy on the lam, riding with desperados in the southwest comes to mind...).
All of this is to say: I actually prefer the writings and activities of the early SI rather than the later. Detournment, the derive, psychogeography; these are regular activities for (temporary) escape (and these things are even better when you're able to escape concrete hell). The later SI, by contrast, is so /political/ while also denouncing politics. The most boring parts of this anthology are the writings on Egypt, Palestine, Vietnam, etc. (Watts is still cool, Paris '68 is still cool), but I don't know if that's because I'm so temporarily and geographically removed. By the end it's clear that Debord is the de facto leader and voice of the SI, and it's a bit heart-wrenching how he's struggling to escape but is so locked in that he can't make his departure without it being an endless series of communiques.
If nothing else, the witty graffiti is perfect for your next tweet.