Debunking performance tuning myths

Being the Education Director for Hotsos, Ric Van Dyke gets to interact with a lot of people so he sees a lot of common myths out there in Oracle-land and his post from last year has several that he debunks.  I thought the one on full table scans was interesting, as I haven't seen a lot of these acting like he talks about, but now I'll keep my eyes open for an example!