Jesus does two dramatic things in John 2. He changes water into wine at a wedding in Cana, and he clears the temple. The latter story I've already covered, but the former is told only by John, so to Cana today I go. It's a village just five miles from Nazareth, so it's no surprise that Mary and Jesus are there. They are probably related to or friends with the bride or groom or both. The fact that Jesus makes 120 gallons of wine for a wedding where all the wine is already gone suggests a big crowd, as does the presence of the disciples ("what's 12 more guys in a crowd like this?"). I suspect weddings were their version of the Champlain Valley Fair: everyone comes from miles around, eats and drinks too much, socializes to their heart's content, and eventually goes home.
I could spiritualize about how keeping Jesus in a marriage means the later years will be better than the early ones, and (as I heard from one Catholic brother) Protestants can trust Mary because she will just be telling us what she told the wedding servants: "do whatever he tells you." But the real point of the story is that Jesus performs an amazing, public miracle which "revealed his glory" (vs. 11). As a result "his disciples put their faith in him." In their eyes and those of the wedding guests, Jesus came to the wedding as Mary's son and left as the Miracle Man of Galilee. From that point on he focused on wooing and winning his Bride.