Avot222

1:
He used to say: obviously, this is a further teaching reported in the name of Rabbi Shim'on ben-Azzai.

2:
It is, of course, tempting to understand our present mishnah in the light of what, according to Plato at any rate [Charmides, 163-4], was inscribed above the Pronaos [entrance hall] of the temple at Delphi. The visitor was confronted by certain inscriptions, among them: 'Know thyself' and 'Nothing too much'. But our classical commentators understood ben-Azzai's exhortations in a different manner and there does not seem to be any great reason to depart from their understanding.

3:
The classical commentators seem to understand our present mishnah as warning us not to take any thing or any person for granted. That is to say, that we should never act on the assumption or presumption that a certain person or a certain thing cannot or will not do us good or harm – whatever the case may be.

4:
Rambam writes:

Therefore, do not underestimate them.

5:
Rabbi Ovadya of Bertinoro draws a similar conclusion:

In short: there is a time and a place for everyone and every thing, so it is wise to bear in mind at all times their possible influence on our fate.

Before I set the closure on discussion concerning the three sins for which woman may die in childbirth I had received a couple of messages on that topic. it seems to me only right and proper that I should relate to these messages despite the closure. Yehuda Wiesen writes:

This passage has bothered me for some time. Why are these three sins deserving of death in childbirth? Are they women's sins, so deserving of uniquely women's penalty? Are they capital offenses? Further, where is mercy and teshuva? Can only death atone for these sins?

I respond:

I believe that in past responses I have answered Yehuda's first three questions. The sages were not saying that women who commit those three sins (sexual intercourse during menstruation, separating Ĥallah from the dough and lighting candles on Shabbat and festivals) are deserving of death. All they were saying is that should such a terrible tragedy occur, that a woman dies in childbirth, it might be because she did not observe those three mitzvot, which are not capital offences.

As for Yehuda's last question we can state quite categorically that (barring certain very unique cases which need not concern us here) the teaching of our sages is that

If such is the case of "wicked people and apostates" how much more so must it be the case of a poor woman who did not light her candles!

Woty Regan also sent me a message on this topic, but I believe that she has seen my answer in my previous responses.

In Avot 217 we had occasion to mention the yetzer tov and the yetzer ra (the good and base human instincts). Ed Frankel writes:

When I was a graduate student, studying educational theory on a level I had not previously attempted, I studied yetzer hara and yetzer hatov. We all know that one cannot be successful without both as part of our psychological makeup. The Sages, as I believe we studied in another mishna, pointed out without yetzer hara there would be no procreation….. It seems to me that the yetzer hara and yetzer hatov are rabbinic descriptions of what Freud calls the id and the ego.

I respond:

Ed's assumption needs no corroboration from me, but for what it's worth: I am in full agreement.