I'm a data centred web dev so a little different to many types here - but I like a variation between grinding out code (mundanity) and solving intractable problems and designing sensible architectures and data models. I'm senior enough to allocate the junior devs to do the grunting when I get bored of it now - and as it is still hard enough for most of them, generally that's cool.

My diasasters tend to be of the 'this remuneration report is showing £351.07 out from the £1,271,234.09 it should be' nature. That's when I know I'm in for a 3 day brainache.