Enterprise applications are (usually) the applications that people have to use, whereas consumer applications are (usually) those that they choose to use, and so I would argue they are where you can have the biggest effect on user-happiness.
Gains in user happiness on consumer applications are mostly incremental – the standard is pretty high, it has to be, because the switching costs are (usually, with some exceptions) so much lower. But enterprise applications usually win out on different metrics (security!) and user experience lags behind in importance. So if you can create a truly beautiful enterprise application, that wins out on the metrics the people who evaluate (but often do not use) it care about, the users (who likely have no part in the decision process) will be so much happier as a result.
I really like this article on application design and how bad design is exhausting.