straight lines

{rant} So I'm cutting drywall and a piece is off a bit. I cut another and that one is off as well. I measure several points along the surface but each segment drawn with my level has a slight curve. I'm creating subtle scalloped lines. The level is not slipping and if I flip it over, thus expecting now a convex arc, is still concave with another identical scallop. I work out that the plastic level is flexing as I cut. On the one hand, I'm angry that someone would sell such a hunk of crap. On the other, I'm happy to have found the source of my inability to get it right.

I now own two additional high-end pieces of equipment. A drywall specific aluminum straight-edge and a bomber aluminum level with a rotating bubble. I hate crappy equipment. Of course now, if I'm off for any reason, I have nobody to blame.{/rant}