Contentment and happiness are blessings that are given only to those who follow the straight path. Muhammad (bpuh) left us upon one end of this path, and at the other end of it are the gardens of Paradise.
(And indeed we should then have guided them to a Straight Way)
(Qur'an 4: 68)
By happiness we mean this: when one adheres to the straight path, though he may be afflicted with hardships along the way, he is confident of a happy ending and a future abode in Paradise. As a result, he will follow the Prophet (bpuh), who spoke not from his own desires, who was immune to the whisperings of the Devil, and whose sayings are a proof upon mankind.
(For each [person], there are angels in succession, before and behind him. They guard him by the Command of Allah.) (Quran 13: 11)
One can sense the joy of a righteous person by his mannerisms and by his treading the straight path. He knows that he has a Lord and that he has a role model in the Messenger (bpuh); he has the Book of Allah in his hand, illumination in his heart, and a conscience that prompts him to do well. He is advancing to a greater state of bliss and is always striving for betterment.
(This is the Guidance of Allah with which he guides whosoever He will of His slaves.) (Qur'an 6: 88)
There are two paths: one that is figurative and the other that has a physical reality. The first path is that of faith, which one treads in this transient life e a life that is fraught with temptations and desires.- The second path is in the Hereafter. Every person will have to go across that second path in order to reach Paradise. Anyone who fails will plunge into the Fire. This path or bridge is teeming with spikes. Whoever is guided to the path of faith and belief in this life will safely cross the path of the Hereafter---the speed at which he crosses will be proportional to the level of his faith. And know that if one is blessed with being guided to the straight path, his worries and anxieties will quickly vanish.