Plenty of Saints are controversial figures. St Augustine of Hippo is one as is St Teresa of Avila. I believe Mother Theresa has now joined their ranks, that will please you
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I never prayed to Saints, or venerated them. The canonisation process seems unnecessary, time and money would be better spent elsewhere. Some Saints are very interesting and inspiring. I loved reading about St Therese of Lisieux when I was young - the less sentimental stuff - and a more recent Saint, Maximillian Kolbe certainly deserves an accolade, imo. However it has never been my belief that we need intermediaries. On the other hand, it doesn't hurt to ask people to pray for you.
The Catholic Church teaches that anyone in Heaven is a saint (not a capital S) so there are plenty of unsung saints. We are all called to be saints.
The tradition of veneration of the Virgin Mary seems to have started in the 2ndC. It's extremely popular, and extravagant, in South American countries and some of it can be compared to earlier, pre-Christian, religion. She is a sort of earth mother figure. Over here we make less of a deal out of it, some Catholics find it embarrassing and play it down. Yet is all very dramatic and beautiful in its way, and quite feminine. The 'high' Church of England go in for a lot of that, understandably in deprived areas where beauty and colour are a stark contrast to drab, poor surroundings.
Pope John Paul ll had a particular devotion to the Virgin Mary. The Polish church in his time hung onto its traditions, understandable as it was unpopular in the eyes of the state. He also appreciated her as a mother figure, having lost his own mother at a young age.
I'd have thought you'd have known all this, it has come up so often over the years on forums.