Not trying to act like anyones Dad here but I would say 90% of messages I get from people freaking out or getting super worried are because people are on margin and/or buying options.
I have personally never even messed with margin believe it or not but I have played options many times and although I've won more than I've lost its still not worth the added stress imo.
Selling options is a different story but other than that I would say 98% of people should just be sticking to shares.