Project planning? I don't think I've ever seen a software engineering project where the costs don't overrun and the tasks don't take longer than they're 'meant'

Project planning? I don't think I've ever seen a software engineering project where the costs don't overrun and the tasks don't take longer than they're 'meant' to. Waterfall, agile, anything else... they all seem to fall apart in everyday life with development related tasks. Similarly, feature/scope creep seems to be a big problem in this field too. It's not as common as projects taking too long/costing more than expected, but still pretty common none the less. Usually because someone didn't actually ask the customer what they needed before building it, or feel like telling someone that they can't just 'have extras thrown in for free midway through development'. Documentation too. We desperately need more people to willing to write/update that stuff, especially where free software is concerned.