Sharepoint "unexpected error has occurred"

Is this a dreaded error that leaves you high and dry trying to find out the cause?
Recently discovered (in another blog page (bad i missed the orginal link)) a very good way of getting the call stack information instead of this highly informative single line message.


Change the callStack value of safemode node in web.config from false to true and reload the page again.
BTW, some of the possible reasons for this message include
1. having a form inside the aspnetForm in sharepoint - usually through user controls (of course if you manage to wrap the inner form within an Iframe then that is ok)
2. If a webrequest is made from the webpart and there is a connection failure that is unhandled in the webpart
and more.. I will add to this list, as i find