'Slapdash' describes the method, not always the results. As in 'hasty and careless in execution' or 'In a reckless and haphazard manner.'
Sometimes it all comes together, other times it doesn't. That's the main criticism I have of my own work, I'm inconsistent. Sometimes I'm really impressed with my stuff, and on another day the output won't look so good. It's all down to me because I know I can be lazy and careless, but I don't really want to change my ways. Usually 'getting it on the table' wins over 'must impress those buggers at LAF!'
Also it usually looks brilliant to me until I take a photo of it, and then you notice loads of things you didn't spot before that could have been better. I hate how cameras do that.