I've seen agile in both the good and the bad.
The Good: People who know what they were doing (always helps) and were able to deliver a product from scratch in 9 months. We didn't follow every meeting (no retrospective) because people had shit to do; planning was limited to 2 hours and conducted well. No Scrum Master.
The Bad, nay Ugly: This mostly stemmed from evangelist(s) and Scrum Masters (not all of them tbf) who seemed to me to be absolutely STEALING a living. They created so much bluster and bullshit that you ended up with no requirements, no cohesion, no comprehension, no fucking idea. So when things fell flat on their arse they'd just change the framework. Kanban, Scrum, XP, something else, SAFe all within 12 months.
When you have useless scrum meetings where nothing is achieved and you're sat in a room with some 10 contractors on £500 a day that useless 2 hour meeting has cost your company THOUSANDS, for what? For fuck all!
Lose the idiots and get off the bandwagon or you will spend so much money it's un-freaking-believable. Don't pander to Agile just because you heard someone say it and it's the thing all the cool kids are doing.
Holy shit, flashbacks of such stupidity its overwhelming... nnnnghhh.