Why do some people smoke after prayer, even though "prayer prohibits indecency and evil"?

Whoever prays and then commits sins has not performed the prayer as required. For true prayer, with its humility, conditions, and pillars, forbids indecency and evil. As for prayer without humility, it does not affect its performer and does not restrain him from sins. Prayer should lead the worshiper to the best state, so he must strive to improve it and repent from sins.