What church practices did Martin Luther become outraged by?

Answer 1

Attached below is a English copy of Martin Luther's 95 Theses which contain the Church practices that he was questioning, I think "outraged" might be a bit over the top. Most the practices he was questioning were connected with indulgences, pardons, and confession, however, a quick look through his 95 Theses even by a first year seminarian would quickly reveal that Martin Luther really didn't know what he was talking about, many of the things that he asked for were already Church teaching. I believe that the practice that Martin Luther was most upset about was the fact that the Church asked him to lead a moral life as Luther spent the rest of his life trying to justify why he didn't have to repent and reform his life.

Answer 2

The Roman Catholic Church's sale of indulgences (forgiveness of sins).