Developers opinions and tips for a scrum master

So I would like to ask developers who are in or have been in a scrum team for their opinions regarding scrum and scrum masters and any tips they might have. I want to know what devs really think about scrum instead of asking on a scrum group filled with SMs and POs. Eg. things that worked, things that didn’t, what you hate/love about scrum and your SM and/ or PO