While the MIT license is a fantastic license for those too lazy (or
unable) to understand more complex licenses it's too lax when it comes
to protecting authors (= me). For example, there are no clauses regarding
patents or ownership of source code. This means that patent trolls
could, in theory, drag me to court.

Of course one can still do that when using the MPL, but at least it has
an explicit clause regarding patents. The MPL also provides a nice
balance between the MIT license and the Apache license. I don't like the
Apache license as it requires listing any significant changes in every
changed file.

In short, I don't really care what people do with my software (they
could sell it for millions for all I care), as long as they don't drag
me to court or otherwise hold me accountable for something.