We have ALL at least thought about them once in our life.
Let's first define which is which because Alien's and Extraterrestrials are different from each other.
EXTRATERRESTRIAL: share an analoguous biological foundation with most other sentient beings in creation. So even though they may look different to humans, they do however, have similar corporeal/biological compositions. For example, human blood composition is primarily based on iron (red), other ET's may have it based on copper (blue), chlorophyll (green), etc.
ALIEN: Completely different in molecular/biological composition & function in comparison to humans & extraterrestrial beings. Evolution governing their existence is based on dissimilar biological laws to ours.
Are they real? Do they exist outside of our world on others planets?
I don't even believe so.
I KNOW SO.
I have seen them, I have touched them, they have touched me (in more provocative ways than I can share on here) and my life has been constantly affected and indirectly influenced by them ever since I can remember.
Man from near the star Aldebaran
It's real people.
They do not discriminate against the rich or poor,
Your colour, your race, or where your from.
If they want you, they'll find you.
You cannot run, and you cannot hide.
Contact with other beings happens all over this planet and has done so even before Human conception.
Strange cloud anomaly prompted me to take this photograph in the Thai Country side April 2013. This sky anomaly was not visible to me at the time, however appeared once I uploaded the pictures in my hotel room in Bangkok later that evening.
And direct contact has happened with thousands of people on this planet.