Anyone who learned in Yeshiva knows that the Amoraim (the Rabbis who appear in the Gemara) are portrayed as paragons of virtue and on a level that we can't even approach. However, if you actually learn Gemara we see that they were vindictive, stingy and tried to use technicalities to evade the law. Here are some examples from Gemaras that came up recently in Daf Yomi.
I. Bava Metzia 107b - 108a - The gemara discusses the status of forests bordering on a river. The Gemara states that since they use to pull boats on the river using men on the 2 riverbanks, the owner of the forest needs to cut down the trees on the riverbank to provide enough space for the pullers to walk and pull. The Gemara then states that if a Jew owns one stretch of the riverbank forest but non-Jews own the rest and the non-Jews will not cut down their part the Jew does not need to cut down his part either. The Genara then relates the following story. Rabba Bar Rav Nachman was traveling and saw that the forest next to the riverbank was not cut down. He asked who the owner was and was informed that the owner was Rabba Bar Rav Huna. Rabba Bar Rav Huna had not cut down the forest because a non-Jew owned the other pieces and would not cut their part down. He then told them to cut down the forest. Rabba Bar Rav Huna found out about the incident and promptly cursed the person who cut down the forest that his children should die and this is what happened to Rabba Bar Rav Nachman, his children all died. Rashi explains that Rabba Bar Rav Nachman made an honest mistake he did not know that a non-Jew owned the othe part. Yet, Rabba Bar Rav Huba cursed Rabba Bar Rav Nachman's children.
It certainly seems that Rabba Bar Rav Huna was upset at losing money and therefore vindictively cursed Rabba Bar Rav Nachman.
II. Bava Metzia 84a the story of Rav Yochanan and Resh Lakish. The Gemara relates how R' Yochanan met Resh Lakish who was a bandit and convinced him to come and learn Torah by offering him his beautiful sister as a wife. After Resh Lakish had established himself as R' Yochanan's best student the following incident took place. There was a dispute as to the time when the different kinds of knives and weapons might be considered in a fit state to be susceptible to ritual uncleanliness. The opinion of Resh Lakish differed from that of R' Yochanan, whereupon the latter remarked, "A robber knows his own tools". R' Yochanan alluded to Resh Lakish's life as a bandit, in which a knowledge of sharp weapons was a matter of course. Resh Lakish responded by supposedly denying any benefit he had received from R' Yochanan; "When I was a bandit they called me 'master', and now they call me 'master.'" R' Yochanan retorted angrily that he had brought him under the wings of the Shekhinah. The Gemara then relates that due to R' Yochanan becoming so upset, Resh Lakish became ill. R' Yochanan's sister, Resh Lakish's wife begged her brother for mercy for her herself and her children and R' Yochanan refused. Resh Lakish then prematurely died as a result of R' Yochanan's curse.
Again, we see a prominent Amora gets upset at an insult and because of that curses someone and causes them to die.
III. Bava Metzia 111a - The Gemara is discussing the issur of בל תלין, the prohibition against paying your workers late. The Gemara states that the issur only applies if you hire the workers yourself. However, if you have a שליח hire the workers for you, then there is no issur of בל תלין. The Gemara then relates how מרימר and מר זוטרא would routinely do this (use the other as שליח) to avoid the prohibition of בל תלין. Tosafos comments that of course they weren't planning on not paying their workers on time, rather they were worried that they would forget to pay their workers on time and inadvertently violate the prohibition.
Here we see a willingness to use a loophole to avoid violating an issur while harming someone else. The moral thing to do would be to specifically not use a שליח and put yourself on the hook for the issur so that you would be even more motivated to pay your workers on time. Instead they took the loophole so as to avoid the issur on themselves while harming the workers by not paying on time.
There are many many more examples, these are just ones that I have seen in the last few weeks of learning Daf Yomi.
I have said many times, Daf Yomi is bad for your spritual health because you learn every daf of Gemara skipping nothing and you see all the silly, ridiculous, bad things in the Gemara that are always skipped in Yeshivas.
For more examples see my post Were the Amoraim/Tannaim paragons of virtue? more