Science fiction — especially on TV — does a wonderful job of ignoring obvious problems, or waving them away with a little exposition. The most obvious issue is translation; whether it be Babel fish, universal translators, or a field imparted by the TARDIS, somehow various disparate cultures all manage to be understandable to one another in modern English. Idioms translate perfectly and, even more incredibly, lips synchronise with the ‘translated’ speech.
Translation isn’t a problem in the Stargate universe, where cultures that have descended from people who left Earth thousands of years ago seem to have evolved their languages to be very close to modern American English. No need for translation devices if everyone conveniently speaks the same tongue.
But although this lucky example of parallel linguistic evolution cures one problem, the stargate itself introduces many others. Its physics-bending rules of operation seem somewhat ‘flexible’ depending on what is demanded of the plot at any given time. So it’s not surprising that the orientation of stargates tends to be ignored — you can apparently fly your puddle jumper into an orbiting stargate any way you wish, and you’ll emerge in Atlantis the right way up.
Perhaps there’s a self-righting mechanism in the stargate system — goodness knows there are enough safeguards in the operating system that overriding them is a key point of many plots — but how does it know which is the right way up for a puddle jumper, or wraith dart?
G1: I still can't believe we had this Stargate in a museum for all those years, thinking it was just another archaeological artefact we'd dug up in the desert
G2: But at least we know its real purpose now, and we're restoring it back it to its original location
G2: Just in time, too. That must be the visitors from Earth arriving
[Scene shows the SG-1 team falling to the floor from the "top" of the stargate]
G1: Oh… so it needs to go *that* way up…