With three laws R’ Gamlial was stringent like Bais Shammai:]

1. He did not insulate a hot food on Yom Tov for a Shabbos which was right afterwards if he did not specifically make an eiruv tavshilim using an insulated item.
2. He did not put back a menorah which was taken apart.
3. He did not bake large amounts of bread at one time. This is what he saw in his father’s home. The chachmim said, what should we do to your father’s house that we stringent on themselves and lenient to the whole Klal Yisrael.

Beitzah 2:7

R’ Gamlial was lenient on three laws;

1. You are allowed to sweep on Shabbos between beds that you lean on to eat. [Sweeping dirt floors is prohibited as you might come to smooth out a floor. In this case it is a small area and R’ Gamlial was lenient]
2. You can put incense on coals on Yom Tov.
3. You can roast a kid on a spit on the seder night.

The chachamim say these are all prohibited.