when the "why" never ending.....

My boys still in "why why why" stage, especially Cruz.

During our recent trip back from Tanjung Sepat, it's already 9.30pm+, i am dead tired, in the car, two of them still very energetic, chatting, talking, and Cruz start his forever "why" questions again. When he heard the GPS said, "turn left, another 500m turn right, keep to your right/left" He keep asking "why it said have to turn, why it said have to stop, why it said have to be careful on the turning?" After i explain and explain, the answer will always lead to another "why" questions. I told him, i am tired, can i rest ( i got a headache that time).

After a while, i saw him rub his eyes, so i asked ......

Me: Cruz, WHY you rub your eyes? You tired?

Cruz: No, my eyes got sand.

Me: WHYyour eyes got sand?

Cruz: because just now i go to beach.

Me: WHY you go to beach?

Cruz: because i like to play at the beach.

Me: WHY you like to play at the beach?

He stopped and look at me and a bit mad, and start show me he is "angry"!!! I cannot stop laughing and he get even mad! Hub was driving, he also cannot stand what i "did", two of us laugh so loud.

Am i mean or bad, this is the only way i can stop him from asking "WHY".