In the Star Trek: Voyager episode "Meld," Neelix, who often tries to bond with his crewmates by learning about their cultures, mistakenly believes that all Vulcan holidays are the same. This misstep is part of his effort to engage with the diverse traditions aboard the USS Voyager, highlighting his well-meaning but sometimes flawed understanding of other cultures.

In another episode, "Investigations," Seska derides Michael Jonas for his failure in their covert operations by sarcastically questioning if their communication was merely for exchanging holiday greetings. This comment underscores Seska's frustration and the seriousness of their treacherous activities, contrasting sharply with the more benign notion of holiday greetings.

These instances reflect how holidays, while often seen as joyful and celebratory occasions, can also be referenced in contexts that emphasize their importance or, conversely, highlight the stark differences between cultures and situations.

Bajoran Time of Cleansing

Gratitude Festival (Peldor Festival)

Ha'mara

Christmas: December 25th

Earth Day: April 22nd

First Contact Day: April 5th

Federation Day: October 11th

Halloween: October 31st

Hindu Festival of Lights: Sunday, November 12th

Mazurka Festival

New Year's Day: Janurary 1st

Sadie Hawkins Dance: November 15th

Saint Patrick's Day: March 17th

Thanksgiving: November 23rd

Day of Honor

Kot'baval Festival

Kal Rekk

Rumarie

Tal-Shanar

Festival of T'Plana-Hath was also mentioned in the first draft script of ENT: "Fusion".

Batarael (Haliian homeworld)

Captain Picard Day (USS Enterprise-D)

Commander Riker Day (USS Enterprise-D)

Festival (Beta III)

Red hour

First meal (Meridian)

Lohlunat (Risa)

Mother's Day (Lissepia)

Prixin (Talax)

Ktarian music festival

Anniversary

Birthday

I'm Married to the Most Wonderful Woman in the Galaxy Day (according to Miles O'Brien)

Naming Day (Ferenginar)

Friday, May 8th, 2161 - Background in the Star Trek: Star Charts.

Tuesday, June 30th, 2161 - Listed on a memorial plaque at Starfleet Academy in Star Trek Online.

Wednesday, August 12th, 2161 - In the last chapter of the novel Last Full Measure, To Brave the Storm, and Control.

Sunday, October 11th, 2161 - "It's Federation Day!", a newspaper clipping created for Star Trek Generations but not seen on screen.