Close encounters of a strange kind

It would be nice to learn that there is intelligent life out there but we should be hesitant about them making an appearance on the front lawn. Of course when we see UFOs land, we have a variety of reactions. Do we welcome these new people or do we organize a military confrontation? All these can be answered based on three things: What is the appearance of the ship and the visitors, why are they here and what do we get out of this?

By appearance of their vessel, I'm referring to what we see when we first view the ships. If they are these lumbering giant war machines as seen in Independence Day and War of the Worlds (not the Tom Cruise one) we have a tendency to attack but if the ship is small or looks unarmed we're more friendly to it. This is based not only on the fears of UFO invasions in popular culture but how we view nations and their armies in particular how the Europeans of the mid-1800s saw the Russians as a threat due to their size and ambitious claims. On identity of the visitors, I refer to how the visitors look. If they look fierce, have weapons or wear some brand of heavy armor (like the Alien and Predator), we panic thinking we're about to be killed. If small or human sized and carry human-like facial appearances we act friendlier as we see this visitor as one of our own kind.

Now the purpose of their arrival is another issue. Seeing as how the earth is isolated by other uninhabited words, we believe the likelihood of them discovering us is small. If they do find us and land then we should ask if this was just reconnaissance (scouting out the map) or there is another reason. They may have a particular interest in a resource we have on earth to which we respond positively unless that resource is limited like oil or if the object they need is humans (if that's the reason then we panic and attack). One particularly less reason for them being here is if they need to use Earth as a base. This poses a danger for we do not know if there's some other insidious reason for this or if this is to protect them from another alien race. If the latter is the reason, we tend to refuse the offer and maintain neutrality for numerous reasons like for one, we have no spaceships for defense and our current army is relying on outdated weaponry.

Finally we tend to concern what the outcome of this meeting produces. If this creates a new era of prosperity should the aliens give us parts of their technology, we openly welcome them and opt for an outreach to interplanetary civilization (kind of like Stargate). If the aliens act as a threat we either chooses to sign a peace agreement with them or we fight them. Overall this scenario is used as an example of how new nations who just discover each others existance react to one another.