I use Tarot and it's a very beneficial tool if used correctly, great for meditations and also for any sort of applied energy work. As for 'telling the future'- the future always remains mutable whatever cards or anything else says, what they do do is give a suggestion of direction and probability which needs careful interpretation. As long as you see them in a very broad way things are fine, otherwise you end up with ideas like Grasscarp's Mum who thought (I'm assuming) The Tower? and Death? ( from the description) cards meant a sudden death where that is not the meaning at all necessarily and certainly the cards could not have made anything happen. Treat them with thought and they are really wonderful for self enlightenment and progression, treat them as a set in stone literal message and they'll scare the life out of you at some point- which is not their intended purpose at all.