People commit altruistic acts, and then act selfishly and inconsiderately later in the day, once they feel that they have been good enough that they've earned the right to be a little selfish. In other words, they estimate that they've been good enough at presenting an altruistic image that a few transgressions won't threaten that image.

1. It's not about their image to others. People who were assigned environmentally friendly products were more selfish than those assigned other products.
2. The obvious solution is to commit acts of selfishness and inconsiderateness that seem worse than they really are. Any ideas on how to do slight/no/negative evil but feel very evil? Pulling wings from flies, maybe?