The mishna (Avos 5:22) contrasts the character traits of Avraham Avinu and Bilaam Ha-rasha. Interestingly, the Tiferes Yisroel notes that Avraham's very name is an acronym for "av ha-mon goyim – father of a multitude of nations", as he taught monotheism and ethical character to all of humanity. Thus, by emulating his traits, even a non-Jew can become a disciple of Avraham. The three traits of Avraham: a good eye, one who is not jealous of the next one's success; a humble spirit, possessing humility and modesty; and an undemanding soul – one who exercises restraint and self-control. In contrast, those who possess an evil eye, an arrogant spirit and a greedy soul, are classified as followers of the wicked Bilaam.
The mishna then continues with a rhetorical question: how are the students of our forefather Avraham different from the students of the wicked Bilaam? The disciples of Avraham enjoy (the fruit of their good deeds) in this world and inherit the world to come. The disciples of the wicked Bilaam inherit Gehinom (purgatory) and descend into the well of destruction (the mishna cites verses to substantiate the above).
At first glance, we might have understood sentence of Gehinom for the wicked to refer to olam ha-bah, their due punishment in the world to come. However, the Meiri in his commentary notes, in contrast to the righteous who reap reward in this world, the wicked experience Hell already on Earth. Those who suffer from greed, arrogance, and lust cannot and do not enjoy even this world! They cannot and do not enjoy what they have, if others have what appears to them to be more and better.
We are taught in the Talmud (Kiddushin 39b) "the reward for mitzvos is not in this world." In addition, in Avos (1:3) Antignos taught, "be not as servants who serve the Master for the sake of receiving a reward." Yet, our mishna teaches that the very observance of Torah and living its middos (character traits) does provide the highest form of reward (i.e. personal contentment) even in this world.
Shir Hashirim (5:16) states, "His palate is sweet, and he is altogether desirable." Rashi explains that His decrees of the Torah are sweet, as Hashem commands in Vayikra (19:28) "you shall not make a wound in your flesh for one who has died ... I am the Lord." Is there a palate sweeter than this? Do not wound yourself, and for this Hashem promises a reward! The reward is thus not only in the world to come, but here and now He protects and guards our physical bodies, and through the positive noble character traits of Avraham, He enhances and protects our psychological well-being as well. Reb Yeruchum zt"l, mashgiach of the Mirer Yeshiva, noted that it's not only the example cited above by Rashi that enhances our life, but indeed all of Torah is a formula for "ashrecha baolam hazeh", your well-being in this world.
The above is encapsulated in the insightful teaching of the Vilan Gaon – in his Aderes Eliyahu on Vayikra (18:5), "you shall observe My decrees and My laws, which man shall carry out and v'chai b'hem - by which he shall live – I am Hashem." The Gr"a understands v'chai b'hem literally. The observance of mitzvos yields goodness and quality to our lives. Thus, he understands the end of the verse to mean I am Hashem, who is instructing you to observe these mitzvos because I commanded them, rather than observe them because they are good for you and provide meaning and quality to your life.
Shabbos is the yom m'nucha and kedusha. In addition, it binds and bonds the family. Without a proper halachik observance of Shabbos, one not only loses out on the rituals of Torah, but also on the social benefits as well.
The expression of "sweet revenge" is antithetical to a Torah personality. To the contrary, the Talmud (Chulin 89a) teaches that the world exists only on account of the one who restrains himself in strife.
Finally, the Rama concludes his commentary to Orach Chaim by citing the verse "tov lev mishta tamid", which the Gr"a understands to mean a person with a generous heart and disposition enjoys a state of being of contentment and happiness, always.