Cross is similar to angry, only less intense. It is used to express anger at minor matters.
You left the cream out all night. Now I'm cross with you.
vs.
She left me for another man. I was so angry with her I wanted to scream.
A quote from the MW Dictionary of Synonyms (without examples here):
"Severe is applicable to persons and their looks, acts, thoughts, and utterances or to things (as laws, penalties, judgments, and styles) for which persons are responsible. In all these applications it implies rigorous standards of what is just, right, ethical, beautiful, or acceptable and unsparing or exacting adherence to them; it not only excludes every hint of laxity or indulgence but often suggests a preference for what is hard, plain, or meager (a severe teacher). Very often the word suggests harshness or even cruelty (severe criticism)."
"Harsh suggests a nature that is unfeeling, cruel, and indifferent to the pain it inflicts (a harsh critic) or when applied to things, effectiveness in promoting discomforts or in imposing rigors (a harsh rebuke)."
Compare the following examples (taken from different sources):
The country has come under severe criticism for its human rights record. [strong, neither bad not good]
Many people feel the punishment should have been more severe.
It may seem harsh to punish him, but he has to learn that this kind of behaviour is unacceptable.
He later regretted his harsh words. [negative]
He accused her of being unduly harsh. [negative]
Nothing can justify such harsh treatment of prisoners. [negative]
Best Answer
The idiom for "to" is "Does that seem ok to you?" or "Does that look ok to you?" The first is a query about the general propriety of something:
The second may be used to ask about an uncertainty the speaker has about correct usage:
"Is that ok with you?" asks whether you have any objections to a situation or a proposal: