Somebody asked me: do I have to attend the services of the Triduum?
The short answer, as it seems to me: no.
Of course there is the Sunday obligation, which certainly includes Easter Sunday. I would maintain that the Mass of Easter Sunday is part of the Triduum, which begins with either Evening Prayer or the Mass of the Lord's Supper on Thursday and spans the three days until Evening Prayer on Sunday. In my Catholic life before priestly ordination, after which such a question became moot, I had always presumed that assistance at the Easter Vigil satisfies the Sunday obligation.
I guess the liturgies of the Triduum are like Ash Wednesday; they're not 'holy days of obligation' but just things that one does. But I don't think they are obligatory in any sense. In fact, the Liturgy of the Hours would even seem to suggest this; because the Mass of the Lord's Supper and the liturgy of the Passion replace Evening Prayer on Thursday and Friday, and the Easter Vigil replaces Night Prayer for Saturday and the Office of Readings for Sunday (I daresay that this is perhaps the only day of the year that some clerics thereby 'fulfill' their obligation to recite the Office of Readings. And why not? If you're only going to say your prayers once a year, what better day than Easter Sunday?), the rubrics are clear that those who do not assist at these liturgies are supposed to pray these Hours. In other words, the Liturgy of the Hours, in providing for those who do not attend the special services, suggests that such is a legitimate possibility.
Even more, though these liturgies are at the heart of the whole liturgical year for us, there could be fine reasons to opt out. The Mass of the Lord's Supper, though it is one of the most deep and beautiful liturgies of the whole Roman rite, can be especially prone to misplaced innovation and liturgical abuse. Somebody who is sensitive to such things might stay away just for the sake of keeping his recollection. On Friday, of course, there are many different prayers and devotions available in addition to the official liturgy. Someone might prefer something else, though the reception of Holy Communion is not to be dismissed.
But how about the Easter Vigil? Do you have to go? Do you have to feel guilty if you would rather not? Well, the Vigil is certainly a spectacular liturgy, and one that holds within itself a superabundance of symbol, meaning, and encouragement. But it can also be very long. Also, because of its intricate nature, it can be given to distracting liturgical disasters. (Everyone has stories. Sitting down for a drink after one Easter Vigil when I was a parish priest, my pastor said, "Well, let's just say this and call it a night: at least the church didn't burn down.") The Easter Vigil can be somewhat focused on the Elect (rightly) and those who are candidates for some combination of Eucharist, Confirmation, and full communion (wrongly) and sometimes these folks aren't known well to the average parishioner. This isn't a good thing, but it's often the situation on the ground. I remember one Easter Vigil before I was in religious life. I showed up to church early so I could pray my private preparation. Ahead of me in the front row were those to be initiated. I had never seen any of them before, and nor did I see any of them at Mass ever again. Over their nice clothes, each was wearing a lovely new brown scapular. I remember thinking it odd that someone should have be enrolled in the brown scapular--if indeed they were properly enrolled--before being baptized. (It's to be worn under the clothing in any case.) In this sense the Easter Vigil can seem like a graduation liturgy for a bunch of people one doesn't even know. And perhaps there are other reasons why someone might decide not to go.
So I guess that's my long answer. Assist and pray through these amazing liturgies as best you can. But if there's some reason why you would prefer not to, don't worry about it. Pray your prayers on your own, including the Liturgy of the Hours if that's something you do or are supposed to do. In your charity, pray for me, as I will in these days for all who support me in the little outlet of this blog.