Reb Eliezer says you must eat 14 meals in the succa on succos, one for each day and night. The Chachamim say only on the first night of Yom Tov, you must eat in the succa. Reb Eliezer also says if you missed one meal, you must make it up on another day. The Chachamim say you can’t make it up.

Succa 2:7

If somebody has his head and most of his body in the succa and his table outside of the succa, Bais Shammai say that it is no good. Bais Hillel says it is okay.

Bais Hillel told Bais Shammai that when they went to visit Reb Yochanan ben Hacharoni and they saw him eating with his table outside of the succa, Bais Shammai says that the chachamim did not say anything, Bais Shammai says that they did say that it is not proper.