why do water come out of my eyes when I'm laughing?

[DavidDonno]

it happens even when im smiling i thought maybe i should start washing my face in the morning, i thought it will go away but nah

 

[JohnClifford]

You can cry with laughter as well as when you're sad.

 

[TheFirstDragon]

Water comes to your eyes to clean your eyeballs and moisten your nasal passages.
If you cry or laugh, you may breathe hard enough to dry out your nasal passages, which in turn causes water to come from your eyes to moisten them.
The brain can also get into the habit of watering your eyes in certain situation.
Notice I didn't use the word you didn't use for this phenomenon.