- Two legs and two arms (yes, I've see the others with octopus bodies and heads like bugs)
- Two eyes and a mouth (or three eyes and no mouth)
- Most of them don't have a nose (wtf?)
- Their vision is in the same light spectrum as ours
- Their hearing is in the same frequency range as ours
- They sense heat and cold like we do
- They wear clothing to cover their naughty bits (or don't have any naughty bits)
- They don't smell really bad
- They don't make obnoxious sounds (farting, snoring) all the time
- They don't leave trails wherever they go
- They understand our body language and colloquial aspects
What if? What if they smell like shit? What if they ooze from all their pores all the time? What if they leave a slug trail? What if they find some of our gestures aggravatingly offensive? Imagine that some of our common names for things sound like words they use to describe offensive things. What if they introduce themselves and have names like "fuck" and "c**ksucker"? Go ahead and smirk and laugh, but what if they sounded so much like that we'd do a double-take? What if reaching out to offer a handshake is a sign of aggression in their culture? What if we look like food to them?
What if they like to be naked and they have six 24-inch penises sticking out from all around them?
What if they have eight testicles that hang from beneath their face?
We all know about culture dichotomies like how cows are viewed in America versus India. How handshakes are viewed in the Middle East, versus Japan or Africa, and how showing the soles of your feet when sitting down is offensive to some cultures, as is offering your left hand to shake (or even wave hello). So we see cows as a source of milk and food in America. They exist to provide milk and be slaughtered for beef. In India they let them walk the streets like we view dogs and cats. What if aliens view horses and dogs the same way? What if they view skin tones in that way? What if brown skin is ok to have around, but pale skin means extra crispy batter coating? What if?
You're probably snickering. Most humans would. That's because we humans know everything. We can predict everything. We apply our logic to predict what can be possible beyond what we've experienced. We are awesome. That's why we can predict the stock market so well.