S1: E7: The Andorian Incident: In looking over the Vulcan star charts, Captain Archer comes across P'jem, a planet with a Vulcan monestary on it, decides to pay them a visit and gets more than he bargained for.
In another instance in which humanity is showing that we have no manners as it pertains to our neighbors, Captain Archer decides to pay a visit to a sacred Vulcan monestary. Nevermind the warnings of advisement from his first officer, T'pol, that they don't really receive guests there, we're so cavalier that we want to go see what there is to see, regardless of the locals' unwillingness to have us "drop-in".
What Captain Archer doesn't expect is that P'jem is also a planet that is positioned dangerously close to Andorian territory, to the point that the Andorians are suspicious that the Vulcans are using the monastery to cover up a base to spy on them. When the crew of the Enterprise arrives they find the ancient monastery in less than favorable condition, with the monks acting particularly irritated - especially for Vulcans!
This is the episode in which we are introduced to Jeffrey Combs' Commander Thy'lek Shran of the Andorian Imperial Guard, one of my favorite of all of Mr. Combs' acting credits in the Star Trek universe. It's here, where Captain Archer and Commander Shran begin to lay the foundation for their eventual friendship & camaraderie that we eventually witness later on in the series.