@Fenreliania y is my least favourite letter, because it has so much potential to be amazingly useful, but instead it represents so many different sounds with no consistent rules for how they should be pronounced.

For example:

at the end of "sky" vs at the end of "quickly"

"you" has a a /j/ sound at the start, represented by a y, but "union" also starts with that sound, but has NO y

the more time I spend thinking about it, the more frustrating it gets...