I had a leak this morning with the supply line with my bathroom faucet. I had installed the new faucet and supply lines about a month ago. Every thing was working fine until this morning.

The supply line that leaked was the hot water line. It is flexible vinyl, 3/8 OD 1/2" Connector (I think that's how you say it). The line is 16" long, probably 3" longer than really needed but it was either 12" or 16". I hand tighten it (remember hand tighten by me and hand tighten by a man might mean too different things). Then I used my wrench to tighten it a 1/4 turn.

So I thought I connected it correctly except it leaked (it leaked at the angle joint meets the supply line). It seemed a little too easy to un-tighten. The cold supply line was not leaking.

Could it have worked it's way loose? Did I do something wrong?
Should I have used a braided steel connector? Could the bow in the line have cause the connection to loosen?

Thanks for any advice.