"In Eregion long ago a great many Elven rings were made. And they were of
course of various kinds, some more potent and some less. To the Elves, the
lesser rings were but trifles, essays in the craft before it was perfected, but
still to my mind dangerous for mortals. But the Great Rings, the Rings of
Power, they were perilous."
FotR, Book I, Chapter 2, The Shadow of the Past.
That's Gandalf speaking (of course).
We've discussed a while back what the powers of the lesser rings might be, but
here's a question: why does Gandalf think that these lesser rings, the ones
that don't slowly turn one into a wraith, are dangerous to mortals? And why, if
they are dangerous to Men, are they not dangerous to the Elves? Lastly, do you
think that any of the other "magic" items on Arda (e.g. Elven swords) have the
same
dangers?