1 - to celebrate that we have arrived to Tom Kipur ( tomorrow ) the day we have been waiting for to atone for & delete all of our sins.
2 - to celebrate that we have many great Mitzvos to perform tomorrow.
Such as fasting , praying , holiday , repentence , vidui etc.
3 - to prepare to have the strength to pray well & to do proper Teshuva.
Now may be a good time for a gem of Torah study.