Jeez I wish Telegram let you undo deleted messages because I deleted a poll from my channel, not realizing it would wipe out the 8-message conversation I had with a member. I thought the messages would remain visible in the discussion group and just become orphaned, but nah, it zapped them out of existence without warning me, and though it shows I deleted the poll in the audit log, there's no way to undelete it, and it doesn't even show me the messages that got wiped out alongside it.
Telegram is really cool but also I think they should stop adding new features and spend a couple updates refining how their current system works. Because it could be a whole lot better...