Not just annoying - DANGEROUS and time wasting: I tried to delete the annoying bits of a conversation, and lost all the important bits too.
Then I went behind the scenes to retrieve the ones I wanted from the bin, and made a fatal mistake of pausing the cursor by the "delete forever" button instead of the Move To button. And it doesn't ask for confirmation at that stage, of course. OK that bit was my fault, but I was only there because of the foolishness that is the default conversation view. As you see, I am not a fan, even if I think that the overall advantages of the set of Google tools is (usually) worth the occasional frustrations.
Conversation view DOES NOT WORK. It combines conversations which are NOT related, merely based on similar subject lines (or something) and does not allow us to tease them apart again. We want to organise our own lives, thank you very much, Google. PLEASE TA LEAST WARN US when you add undesirable features into upgrades of your basic tools
Eventually allowing us to get rid of conversation view on the web app was the best clean up of gmail possible, and took far too long for such a trivial reversion!