Shemuel wanted to establish the calendar for the Exiles on his own, but Rabbi Simlai's father didn't allow him because he didn't know the "secret of adding [to the calendar]": Rosh HaShanah 20b
Shemuel not practicing a leniency he had learned from Rav, for himself: Ketuvot 22a-b
Permitted [and even used himself] use on Pesach of barley which had been soaked, so long as it had not fully split: Pesachim 40a
Shemuel considered a Rabbi his Rebbe, to tear clothing when he died, because he had taught him the path of the streams which ran from the Temple: Bava Metzia 33a
Shemuel considered the town of Neherdaa a Karmelit even though its doors weren't closed: Eruvin 6b