Why was it better for man not to have been created?
On Daf 13b it says that Beis Shammai and Beis Hillel took a count and decided that it would have been better for man not to have been created than to have been created. And now that he has been created, let him investigate his past deeds, or, as others say, let him examine his future actions.
We can explain this gemora as follows: They “took a count”, that is, they considered the number of the mitzvos, and they saw that the number of negative commandments exceeded the number of positive commandments - 365 versus 248, and therefore they agreed that it would have been better for man not to have been born, since he is more likely to lose than to gain. But this then raises the question - why therefore did Hashem create man?
The answer is that we know that Hashem combines the conscious thought that a person has when he intends to do a good deed together with the good deed itself, but does not do so with bad deeds. If so, every positive mitzvah that a person does will be considered as if he has done two mitzvos, and consequently the number of positive commandments will be far more then the negative ones.
This is the advice that the gemora concludes with - now that he has been created let him investigate his past deeds, or examine his future deeds. That is, he should do the mitzvos with both conscious thought and deed, doing them for the sake of Heaven, and then he will be more likely to gain than to lose. Then it will be better that he was created then not created.
What was special about the teachings of R. Eliezer ben Ya’akov?
On Daf 62b it says that the teaching of R. Eliezer ben Ya’akov was the size of a kav (i.e. small) but clean.
Rashi in Gittin 67a explains that this means that although he did not teach as much as his fellow Rabbis, that which he taught in the Beis Medrash was called clean because the halachah was always according to his opinion.
Another way to explain this teaching is according to the gemora in Pesachim 3a, which says that the Torah used eight extra letters in order to avoid using a gross expression. From this we see that one who wishes to speak cleanly usually has to use more words. But R. Eliezer ben Ya’akov, even though he spoke briefly like the size of a kav, nevertheless his speech was clean.