It is such a widespread idea. Many accuse the church of being hard, bitter, against joy and in favor of sadness. with a harsh God who loves to make people suffer, and morbid fear of hell.
  Why do they say so and how can we answer?
Well, there are some pains that are inevitable and incurable no matter how optimistic one is. There are also some commandments that are just, right and the way it should be, Commandments that even natural men in past eras obeyed. Only that the modern developed world is too weak too soft, too selfish, so he suffers.
  I wonder how God can be in favor of suffering when we know that 90% of times it is our own sins and sins of the others that causes them? If God loves virtue, then He loves joy. God cannot love suffering without loving sin IMO.
  If catholicism was against good things, then so many art and music and civilization would never exist.
  But as this idea is so common , it must have a root somewhere, can anyone please guide me?
(I have to pass survey in english literature, and can't help hearing such things again and again)

 Nobody answers?

The most bitter losses are those that could have been avoided.  The near misses.  The loss of grace is a very bitter thing.

Contemplation of the world leads to sadness.  The joys of a saintly life are hard for people to understand, appreciate, or believe in.