I've never seen an apple app that has such a user destructive lag as the new ios10 mail app. I am using mail app ever since ipod touch came out and it has never lagged so much. I am using iphone 6s, which is still very fast and not even 1 year old. I do have over 10 email accounts and thousands of unread emails, however, this is not an excuse for lag because it never lagged in ios9 or before that. Anybody experiencing the same issue? What happened to the buttery smooth iOS experience we once had? here's the video showing you how serious it is.