I'm not complaining about the length of mass on my niece's first communion, only noting how long it is relative to other busy mass days. The First Communion Mass is a special 2:30 pm mass, so its not like the regular parishioners came in and were surprised by this.
For the record, the longest Catholic service (its technically not a mass, as the Eucharist is not celebrated) (in my personal history) are always Good Friday. Its the veneration of the Cross which contributes to the length of the service.
Any Eastern Orthodox wedding service can be long. My older brother's was over 2 hours, and I was told by the wife's side that it was 'short'.