How seriously should we take sin?
Very seriously
What is so wrong with grading/evaluating sin?
There is nothing inherently wrong with grading/evaluating sin.
However, there is a danger in how one might use such grading. Such dangers can run from despair to presumption…
There are some sins that cause more harm on a grand-scale to others and to one’s self? There are others are simply slights. I understand sin is bad and wrong. So long as I am alive, I will sin. Not only this, people around me will always be sinner. What the heck am I supposed to do? It is in our human inclination to be sinful.
Do your best and rely on God’s mercy.
I have a difficult time agreeing with an attitude, unexpressed thought, etc being a sin.
Someone already mentioned Jesus’ comment about lusting in one’s heart - So please consider that fact carefully.
I will simply add that what one thinks reflects what is in ones heart at that moment. So - whether it is expressed or not - the thought is either good, right and loving or it is not. If it is not good right and loving, we are in violation of Jesus commandment to love one anther as He has loved us.
What harm does it do it others if I think I am better than they are, if I think they are stupid (especially if they actually are). What if I am better than someone at something, what is so wrong in thinking that. And is there such thing as too much honesty? My sister said something a long the lines that just because something is true, does not mean it should be expressed.
What might be a better question is what harm does it do to YOU to think these things. Your questions strike me as coming from a young person who is struggling with pride, is perhaps too judgmental, and lacks proper humility.
If you are smart, others will know this without you telling them.
If others are not as smart as you - others will note this too. You need not make this known.
If you are better than someone at one thing, they might be better than you at another,
And by the way, I totally agree with your sister.
Is there such a thing as too much honesty? No - but there is such a thing as too much talking.
Peace
James