Our Gemara on Amud Aleph teaches the following:

Rav Sheshes said that Rabbi Elazar said in the name of Rabbi Elazar ben Azarya: From where is it derived with regard to a yevama who came before a yavam afflicted with boils that one may not muzzle her, i.e., she cannot be forced to enter into levirate marriage, and he is compelled to release her by ḥalitza? As it is stated: “You shall not muzzle an ox while it treads out the grain ” (Deuteronomy 25:4), and, juxtaposed to it, is the verse: “If brothers dwell together” (Deuteronomy 25:5), which begins the passage that deals with the halakhot of levirate marriage. This teaches that just as it is prohibited to muzzle the ox, so too, one may not muzzle and ignore the complaints of a yevama who does not wish to marry a yavam afflicted with boils.

I will share a couple of interesting observations about this derasha:

The Chasam Sofer (Responsa Likutei 15) actually considers this an obvious point not requiring a derasha. He reasons, if the rabbis allow for a woman to divorce a man whom she finds to be repulsive and not be forced to stay married, how could we think that the rabbis would allow for Yibum to occur? 

(In both cases, the rabbis force the divorce or chalitza by “strongly” encouraging the husband or yavam to give the Get or chalitza. This “encouragement” can extend to even beating him if he refuses to give the Get “voluntarily”, see Yevamos 106b. This is the famous situation discussed by Rambam Gerushin 2:20, that once he has no choice because he is being beaten, his Jewsih heart responds, and he actually gives the Get with full intent.) 

The Chasam Sofer answers that since she got married already knowing what the brother looked like, we might think she already accepted that she might fall to Yibum. Therefore the verse teaches us, even so we do not make assumptions and accept her objections to yibum.

The Chasam Sofer describes these enactments as stemming from the directive of “The ways of the Torah are ways of pleasantness.” (Mishle 3:17). It’s a bit ironic but also understandable that, in this case, though it stems from “ways of pleasantness” by relieving this woman of an unbearable situation, another person is being beaten and forced to comply. We see from here that sometimes the route to achieve pleasantness might be through not-so-polite or pleasant means.

Also, in this situation, the principle of pleasantness is being applied to justify rabbinic enactments and interventions to mitigate Torah situations that are too difficult. One might ask, if the Torah is supposed to be pleasant, why did the laws have to be so difficult that the rabbis needed to mitigate it?

This is not really a question because all laws, by nature, have specific situations that cause individuals harm. Laws, and halakha because it is law, by nature will be made to benefit most people most of the time. When halakha functions as law, that is a societal process, it cannot escape the physical nature, quality and limitations of law.  By example, even though a Succah is a Torah idea, there is no way to escape that if it were a square, it would contain 360 degrees in its angles, and any other rules of physics. It is specifically the role of the rabbis to use enactments, loopholes and other means to adjust the law when a situation comes up that needs mitigation according to their wisdom. 

The Rambam makes this exact point in Guide for the Perplexed III:34:

⁦It is also important to note that the Halakha does not take into account exceptional circumstances; it is not based on conditions which rarely occur. Whatever the Law teaches, whether it be of an intellectual, a moral, or a practical character, is founded on that which is the rule and not on that which is the exception: it ignores the injury that might be caused to a single person through a certain maxim or a certain divine precept. 

For the Law is a divine institution, and [in order to understand its operation] we must consider how in Nature the various forces produce benefits which are general, but in some solitary cases they cause also injury. …From this consideration it also follows that the laws cannot like medicine vary according to the different conditions of persons and times; whilst the cure of a person depends on his particular constitution at the particular time, the divine guidance contained in the Law must be certain and general, although it may be effective in some cases and ineffective in others. 

If the Law depended on the varying conditions of man, it would be imperfect in its totality, each precept being left indefinite. For this reason it would not be right to make the fundamental principles of the Law dependent on a certain time or a certain place; on the contrary, the statutes and the judgments must be definite, unconditional and general, in accordance with the divine words: "As for the congregation, one ordinance shall be for you and for the stranger" (Num. 15:15); they are intended, as has been stated before, for all persons and for all times.

In other words, the idea that a woman must rely on her husband for a divorce and the husband must agree to divorce voluntarily is a deep Torah value. It might feel incongruous to our ears and seem to be a lack of pleasantness but there must be a divine long term societal benefit in making certain aspects of entering and leaving marriage unequal in power distribution between the man and woman. Yet at the same time, there must also be benefit in the rabbis being aroused to mitigate and protect the women. In yesterday’s Psychology of the Daf (Chaggigah 3) we talked about how Torah derived from a derasha represents a stronger striving toward God. The rabbis' mitigation of the Torah may even be a more powerful fulfillment of ways of pleasantness than an original law. Here too, all of Torah is one process. The literal and rule of law in the Torah emphasizes one aspect, while the rabbis emphasize another, in order to yield an ultimate truth.