One feels the satisfying feeling of Sabbath holiness when, on Friday evening, one has washed and changed into holiday clothes and enjoyed a good meal and rested a bit.
But an identical feeling could be experienced on Wednesday, if one washes and dresses up and eats well and rests.
Could then the feeling of Sabbath holiness be a delusion, a sum of purely physical sensations?
The trouble is that there is an inbuilt mixture here of the experiences of the body and the soul and it is not easy to separate them.
In the case of Shabbat, the mixture is not dangerous; it is even essential to the joy.
In other cases, however, it can be dangerous.
For example, in the event of great exultation, a person might feel he has suddenly reached a very high plane of spiritual potency.
Indeed, any imbalance in the mixture of the worlds is apt to cause trouble.
One may learn this lesson from the instance of Rabbi Elimelech, who ordered his Chasidim to refrain from wine and liquor during the latter part of Succot and especially on Simchat Torah–and this precisely because Simchat Torah is a special time for joy in the Torah.
According to Rabbi Elimelech, if the joy of Simchat Torah is mixed with half a bottle of vodka, there may be some difficulty in distinguishing it, because the sensations are similar.
As one of the Sages remarked, a person who takes pleasure in good food on a feast day is often enjoying his belly and not the holiness of the occasion.
–Rabbi Adin Steinsaltz
From The Long Shorter Way by Rabbi Adin Steinsaltz