The Talmud in Masechet Sanhedrin tells a very puzzling story. It describes the efforts of Timna, the daughter of one of the kings descending from Eisav.
This princess was attracted by the teachings of Avraham Avinu. She was prepared to be a simple maidservant and forego her royalty, in order to be part of Am Yisrael.
Surprisingly, the Gemara describes her rejection from all three of the patriarchs, Avraham, Yitzchak, and Yakov. All three felt that she was not converting for the right reasons.
This was similar to the days of David and Solomon, who also did not accept converts. The same reasoning was applied in both instances. Our leaders wanted to be certain that those desiring conversion, are doing so, because of embracing the G-d of Israel. They did not want converts who wanted to join because they were in awe of its leaders, and the movement they were leading.
It appears that this rejection was a serious error in judgement. Timna became the concubine of Eliphaz, son of Eisav. She bore him a son, Amalek, the archenemy of the Jewish people.
This story in the Gemara is definitely teaching us a lesson. Most likely, Amalek would still have emerged. But perhaps we are being taught how we should be extremely careful in all the choices and decisions we make. The trivial may not be as insignificant as we think.
Everything we do can have long term effects, for the good and for the bad. Taking meticulous care in our decisions is far more important than we may realize.