Like a giant game of Chinese whispers through time and age, just screwed up most of the time.
Kind of, yes. And the Christians stole all their major festivals from the pagans.
Christmas? The Christians mixed it in with Yule, the pagan festival celebrating the Winter solstice. Even know WHY you put Xmas trees in your house? You probably don't even know. It's because Winter is a very dark time, so the evergreen became a symbol of everlasting life. Vis a vis pine trees, holly, yew and ivy.
Easter... ever wonder why is has no set date? Easter takes its name from the goddess Ostara or Eostre, who was honoured in the month of April at the time of year when the land became more abundant and fertile. It is also where we get the name for the hormone eostrogen.
The goddess has the head and shoulders of a hare, which is also symbolic for the moon since the hare was very closely associated with Freya and Hecate. The hare, for this reason, also represents Spring and the rebirth of the Harvest. Both the moon and the hare were thought to die and be reborn every day, therefore the hare is also seen as a symbol of immortality.
Eggs are obvious symbolism for birth and new life, and the entirety of creation. The yellow yolk came to represent the Sun and the Sun god, so this is particularly relevant to this time of year when the light half of the year begins.
Hot cross buns, for their part, come from the Celtic cross, with the circle shape of the bread representing the round outside of the cross. Two equinoxes, two solstices, four seasons, four directions. The circumference is the cycle of the year with the point of balance at its centre.
Easter has no set date in the calendar. It falls on the first Sunday after the first full moon following the vernal equinox, this is why Jesus' "rising" has no set date.
Absolutely every major festival from May Day to Midsummer to Hallowe'en has Pagan roots, all to do with the cycle of the year, birth, death and rebirth and the Harvest.