For example – walking through grass. No, really:
Rami b. Hama, citing R. Assi, ruled: A man is forbidden to walk on grass on the Sabbath, because it is said in Scripture: And he that hasteth with his feet sinneth. (Prov. 19:2)
The problem here is not the walking but that unintentionally, one might pull up some grass, either caught in shoes (particularly if there are nails sticking out) or barefoot between the toes! But after discussing these options the conclusion is given:
Nowadays, however, since we have it as an established rule that the law is in agreement with R. Simeon, it is permitted to walk on grass in all the cases mentioned
Rabbi Simeon having established the principle of unintended consequences.
But the Proverbs quote reminds the rabbis of an issue of sexual ethics:
Rami b. Hama citing R. Assi further ruled: A man is forbidden to compel his wife to the [marital] obligation, since it is said in Scripture: And he that hasteth with his feet sinneth.
In fact, not only can a man not force his wife to have sex with him, there is a high value placed on waiting for the woman to initiate:
R. Samuel b. Nahmani citing R. Johanan stated: A woman who solicits her husband to the [marital] obligation will have children the like of whom did not exist even in the generation of Moses.
An interesting proof is given from the biblical example of Leah who “hires” her husband (Gen. 30:16)! Her children and lineage are honored.
Not only is there modesty in traditional Jewish sexual ethics, there is great importance given to the woman – her needs and desires are given precedence over the husband’s.
Now isn’t that more interesting than a tree?