Karma works:

If karma works why are so many bad people successful ?

Once a king ordered his three ministers to take a bag and go to the forest and fill up the bag with fruits.
The first minister thought that since the king has ordered for collection of fruits, he must collect the best of the fruits in the bag.
The second minister thought that since the king is a very busy person, he may not look very thoroughly into the bag what has been collected and hence he collected whatever he could lay his hands. Thus his bag was filled up with a mixture of good and rotten fruits.
The third minister thought that the king would see only externally how big the bag is and hence he just filled up the bag with all dried leaves and dust.
All the three ministers came back to the court with their respective bags, having executed the order of collecting the fruits.
The King, without even seeing what their bags contained, just ordered that now the three ministers must be sent to separate jails for three months, where they will not be provided with any food and they were only allowed to carry the respective bags wherein they had collected the fruits.
The first minister could spend the three months in the jail by eating the very nice fruits he had collected.
The second one could survive for some time with the good fruits in the bag and later he developed diseases by eating the rotten fruits he had collected.
The Third minister had nothing to eat and hence could not survive.
Moral of the story:
From the above story we understand that we have to undergo the consequences of our own activities.
“You will be suffering your own reactions after your karmas, any single karma you perform, you have to suffer for it. Good and bad, everything, you have to have this reaction. No doubt about it.
,  it is said

“Amongst thousands of cows, the calf finds its own mother cow. Similarly the results of our past karma (deeds) when fully ripened, will find us without fail..