Festivale is torture. I wanted kill Pave after having to repeatedly watch him dance over and over and over again while trying to get the last piece of the set because it's random every time. Toy Day is my favorite because it's an event the whole month trying to figure out what villagers want and it doesn't get as tedious as Halloween, Festivale, or Easter.
I like the toy day event so far it's fast and easy! At first I bought all the items my villagers wanted but, it was a relief to find out that I can just memorize what they asked for and not have to buy a present for them, but I'm really looking forward to april fools day, it sounds mischievous and fun, so that might be my new favourite xD
If you EVER get a chance to play in a Japanese town on Feb 3, DO IT! That's Setsubun, and my favorite holiday in the series. It's Japan-only, but insanely fun! All day long you wear the oni mask, and when you talk to villagers outside (inside ones always seem to lose their beans somehow), they'll throw beans at you! They'll say localized version of "oni wa soto! fuku wa uchi" which literally translated would be something like "Evil demons out! Good luck in!", but localization will change it to stuff like "Bye bye bad luck! Hellooo good fortune!" It's cute as anything, and I highly, HIGHLY recommend it!