We live in a generation in which many seek chumrot, religious stringency. This can be most positive, hamachmir tavo alav bracha,a blessing accrues to one who is stringent. This can also be most negative as oftentimes chumrot do more harm than good. Chumrotcan be wonderful when one is observing the entire gamut of mitzvoth appropriately.But to add a chumra in one area of practice  while at same time being lax in another area is not only generally[1] misguided but risks causing a chilul Hashem[2]
Chumrot are meant for the pious and those who are truly pious are few and far between[3]. In addition to the need for a chumra to be appropriate on a personal level there is an even greater need to guard against inappropriate chumrot meant for the entire Jewish people. Even if such might be warranted on some micro level there is a most serious concern that a new chumra, is motzee la'az al harishonim, casts aspersions on previous generations. If previous rabbinic figures accepted a practice can we reject such without belittling them? Are we so great and they so much less so that we should search for new and improved ways of keeping our tradition[4]?
As we have noted in our previous posts a get must be written lishma, with proper and specific intent for the divorcing couple. It is for this reason, at least according to Rabba, that an agent wanting to bring a get must say "before me it was written and before me it was signed". Presumably this means the agent must watch the entire writing of the get in order to ensure it was actually written lishma from beginning to end. And so Rav Ahi, "the appointed one i.e. expert, on Gittin" told Bar Hedya that he must "stand" over the writing of every single word of the get (Gittin 5b)Bar-Hedya then came to Rav Ami and Rav Ashi who told him such is unnecessary. "And if you say I will be strict, you will be found to be casting aspersions on the earlier ones" who did not observe such a chumra. While watching over the entire get is unnecessary the Gemara does not say how much one must watch over. 
The Gemara then relates how Rabba bar bar Channa oversaw the writing of a get actually only witnessed the writing of half of the get.Rav Elazar assured him he need not worry "even if he only wrote one line lishma more [watching] is not needed." Once part of the getwas written lishma we may assume - and that's all it is - all was written lishma. Rav Ashi went a step further only requiring that one hear the paper and pen being prepared. When one hears such one can rest assured that the get is being prepared for this couple and one is not using a previously prepared and hence invalid document. Jewish law follows Rav Ashi and this is a case where chumrot are unwarranted. 
It is worth noting that the prohibition of adopting stringencies that previous generations did not is said in relation to a get, an area of law where the repercussions of a mistake are most severe. Make a mistake and the result is adultery and illegitimate children. This area of law is both complex and most serious that the Gemara (Kiddushin 6a) advises that only those who are expert is such matters should be involved in them - a practice that is observed to this day[5]. This is especially so according to Rav Meir (whose view we thankfully do not follow) that "whoever changes from the procedures laid down by the Sages for writs of divorce, [the second husband] must divorce her and the child is a mamzer" (Gittin 5b). Yet despite or perhaps because of the seriousness of the matter we dare not question the leniencies of past generations.
[1] Of course people naturally excel some area of mitzvot while struggling in others. It only becomes a problem when the gap is so wide that it brings religion into disrepute. 
[2] As I have often noted the Gemara (Yoma 86a) in discussing the topic of teshuva on Yom Kippur while not directly saying so is pretty clear that those whose comportment in areas of man and man leave much to be desired should make sure to also not observe mitzvoth between man and G-d. To observe the latter and not the former brings about a Chilul Hashem and leads people to distance themselves from G-d.
[3] One who is arrogant lacks the character needed to be machmir. Hence almost by definition one who is machmir must not advertise such a fact. Chumrot are to remain a private matter between man and G-d and no one else need know, except in the rare situation that one's chumra will increase mitzva observance amongst others. This is generally much more likely if the chumrot are in the area of interpersonal mitzvoth.
[4] As Haym Soloveitchik notes in his classic and must read article Rupture and Reconstruction (footnote 22) this concept has gone the way of the dodo bird (I am paraphrasing). It is most ironic that a community which venerates tradition is so ready to change that tradition when it comes to establishing new chumrot. Of course there are times when erroneous practices become commonplace despite the objection of the rabbinic leadership and later leaders may attempt and succeed in changing these practices. There is more that needs to be said on this topic. 
[5] The Gemara's actual language is "whoever is not expert in matters of marriage and divorce should have no dealings with them". Yet in practice almost all synagogue rabbis will officiate at marriages whereas only very few will or even can oversee a get. In addition to being less complex generally the consequences are less severe. While not the simple reading of the Gemara perhaps it is possible that the Gemara's warning was said primarily regarding gittin and kiddushin was only included agar orcha, by the way.