 Acquiring knowledge only for worldly gain or concealing knowledge. People have to understand as well what the point of those sins is. So what happens when you show off? Sure, you make other people jealous. But that's not the big deal. The big deal is essentially that you are getting further away from God because you are deifying your possessions, your objects. Wow, look at my car, how awesome. Look at my house, look at this, look at that. Like this, you're pointing away from God. This is why this is sinful.