Vulcans befriending humans immediately has the same energy as when the crazy crackhead couple moves in next door and you're really kind of concerned for them, but make an effort to be nice and socialize with them anyway just so they don't see you as a threat
Human: "We took the second warp core you helped us build and plugged it into the first one, just to see what would happen.... It blew up. But we got to do some pretty cool science in the process!"
Vulcan looking on in pure astonishment
Vulcan: "Fascinating. You were meant to place that in another ship, or study it for improving your own designs."
In another universe: "Thanks for the warp core, we figured out how to turn it into a Death Star and it really helped save our bacon. Also we put them both in the rusted hulk of some WW2 battleship, best we could do on short notice"