I think the most ridiculous are the promotional PA's. I flew on EZY recently and after landing they hadn't even stowed the speedbrakes before we were subjected to the longest PA I've ever heard about the 'Easyjet sale and to check the website for great fares blah blah blah...'
Also they said 'to help us with turnaround times and to keep our fares low please check around you for rubbish and place it in the bin that the crew will bring around in a moment..' I've never been asked to clean the cabin before getting off before.