My DIY disaster: shelves collapsing at midnight

Last night around midnight, I heard this huge crash from the living room. Thought someone broke in or something, but nope - it was just my DIY shelves giving up on life, lol. Books everywhere, plants knocked over, total chaos. Guess my hardware choices weren't exactly top-notch... or maybe I just suck at installing brackets. Anyway, now I'm thinking of redoing the whole thing properly. Anyone had similar shelf catastrophes or got tips on how to avoid round two of midnight shelf collapse?