In a group discussion about Gluttony having a hidden version in its reverse, that is, Delicacy or excessive fussiness about food, Tim King noted that the same is true for Sloth. Being a workaholic is the same sin expressed in its opposite. He claims the idea is straight from Aquinas's Summa. In my commenting that CS Lewis had mentioned excessive delicacy in Chapter XVII of Screwtape, the patient's mother saying "Oh please, please...all I want is a cup of tea, weak but not too weak, and the teeniest weeniest bit of really crisp toast" as an example of real gluttony, it occurred to me that this might be true for all sins. As Maimonides said "Perhaps the opposite is also true." The heart is deceitful in all things.
So that is two of the Seven Deadly Sins - I will bet the others have their reverses as well.
Lust - It is our sexually-obsessed age that makes this only about sex, but let us go with that for the moment anyway. We all know there is a prudery that cannot stop talking about sex. I knew a girl at college who was very vocal about all those other girls who weren't virgins, but was also convinced that she had had previous lives, and had been a courtesan in one of them. She mentioned it a couple of times.
Greed - Too easy. There are a few. People who are ostentatious in bragging about their eschewing of mere material goods in order to score virtue points or gain status as Common Folk, or Preferring The Life of the Mind. Beware of those who insist they don't care about money. They are greedy for something else.
Wrath - I had a post on people who sign off using "Peace," and explained in the comments that they are often the meanest people in the joint. I have listened to people aggressively talk about how their meditating has made them calmer, and everyone should, too. The problem with the world is that there aren't enough people who do the good spiritually healthy things they do. I can't recall hearing a Christian use prayer aggressively, but I'll bet it happens. We have also the people in America who claim to be antiwar but are mostly just on the other side. Beware those who want to convince you that they are peaceful.
Envy - I'm having more trouble with this one. Maybe that means I've got it bad. Help me out, here. I suppose there are ways of praising others that make you look better than them, but no one can call you on it.
Pride - There is an art to the humblebrag, or making a show of martyrdom. Because pride is the deadliest and most deceitful, there are many of these. We probably all have acouple, they are so legion.Lewis again has the right quote. "She was the sort of woman who lived for others. You could tell the others by their hunted look."