Why do you think Félicité's reaction to Virginie's first communion is so much more powerful than her reaction to her own first communion?

As Félicité watches Virginie receive her first communion, she almost faints from the excitement that she vicariously imagines Virginie to be feeling. When she receives her own first communion, she is reverent, but calm. Perhaps she has a more powerful reaction to Virginie's communion because she has built it up in her own imagination. Just as the anticipation of a thing can be more powerful than its actual realization, when Félicité imagines how Virginie feels, she imagines it to be extremely profound and so experiences that profundity herself. When she actually goes through her own communion, she experiences it much more realistically.