Some transactions are restricted or prohibited, although people may want to engage in them (e.g., the sale of human organs, surrogacy, and prostitution). It is not well understood what causes feelings of indignation or repugnance.  We study two potential reasons: lack of agency of the parties and extreme consequences of the transaction. Limited agency arises, e.g., when one party cannot decide freely because she is not able to reject the transaction offered, a third person who profits from the transaction takes the decision on her behalf, or she is forced to proceed with the transaction due to social pressure. In a laboratory experiment, we ask spectators whether they want to prohibit a transaction or not. We find that transactions with extreme outcomes (listening to a painful tone) are more frequently prohibited than those with mild outcomes (waiting in the laboratory). We also show that lack of agency and extreme outcomes reinforce each other, since the combination of both properties leads to prohibition rates of up to 80 percent.