תנו רבנן: שתי שנים ומחצה נחלקו בית שמאי ובית הלל, הללו אומרים: נוח לו לאדם שלא נברא יותר משנברא, והללו אומרים: נוח לו לאדם שנברא יותר משלא נברא. נמנו וגמרו: נוח לו לאדם שלא נברא יותר משנברא, עכשיו שנברא - יפשפש במעשיו. ואמרי לה: ימשמש במעשיו
For two and a half years, Beit Shammai and Beit Hillel disagreed. These say: It would have been preferable had man not been created than to have been created. And those said: It is preferable for man to have been created than had he not been created. Ultimately, they were counted and concluded: It would have been preferable had man not been created than to have been created. (Eruvin 13b)
THis sounds like a harsh and ungrateful statement, certainly contradicting one of the basic principles that G-d created the world to make good to the creations.
So how did they arrive to this, seemingly heretical, conclusion?