Oddly enough, I can (with a few minutes practice) get my mig welds to be one continuous bead and my teacher didn't like itfor almost the same reasons. But the biggest was not having the puddle bridge the gap. But even when we flipped the pieces over and the joint was in the middle of the puddles path of travel..

I still got the same critique! So I latched it down in the vice and tried to break it, and it finally broke next to the weld! The weld was a good one, it just didn't "look" like the picture. SO I still do it once in a while... it just happens, I don't think about doing it. If the joint opening is wide then I pull the puddle side to side like always.. but when it's tight I just "go continuous".... LOL..