Shabbat 50 - Are branches prepared to sit on them on Shabbat?
It happened once that Rav Chanina ben Akiva came to a certain place and found branches of date palms that were harvested for firewood. He told his students, "Go and mentally designate these branches for us, so that we may sit on them tomorrow (on Shabbat)." Zeiri, who was retelling this episode, added, "And I don’t know if it was for the house of feasting (wedding) or for the house of mourning."
From these words of Zeiri we see that only in such a place where people are preoccupied did Rav Chanina permit a mental designation, but in a normal situation he would require a physical action - tying the bundles - in order to sit on them on Shabbat. Otherwise they would be considered muktzeh, set aside from Shabbat use. However, although the Talmud goes into details elucidating it, the law does not follow this strict view.
Ameimar, mar Zutra and Rav Ashi were sitting together one Shabbat, and they brought them "barda," a mix of aloe, myrtle, and violets. Ameimar and Rav Ashi washed their faces and hands with it, but Mar Zutra did not. They asked him, "Are you afraid that you will accidentally remove some hair from your skin on Shabbat, through the use of aloe? - But the law is like Rabbi Shimon, that it is permitted, since the hair is removed only accidentally!" However, his reason was different - a man should not beautify himself as a woman does. Then what was their reason? - Just the opposite, one should clean and beautify himself, since this brings glory to God. In fact, one must say a blessing on a seeing handsome creature.
Art: Francisco De Goya y Lucientes