Go ahead. Name four days of the week that start with the letter T.
Most people say Tuesday and Thursday and then just stop. Two days. That's it. Brain shuts off completely.
Solution:
But the question asked for four.
The other two are Today and Tomorrow. Technically, both are days of the week. Both start with T. Both are completely valid answers. The question never said "from a calendar." It just said days of the week.
This is one of those riddles where the answer was obvious the whole time. The brain just locked itself into one way of thinking and refused to look anywhere else.
Did you get all four?