1. Cruelty, he hates when people are violent or unkind towards others.
2. Danger to his kin or his friends, his main reason for going alone before taking the Ring — and after, to Mordor was for the sake of his comrades and his friends, so he is extremely protective of them.
3. People placing their lives beneath his because he’s the Ringbearer. For one it causes already impossible responsibility on someone who has the world on his shoulders but also because he would never ask anyone to suffer on his behalf.
4. Being spied on, people getting too close to him, with all his experiences it makes him extremely cagey unless it is someone he trusts.
5. His relatives, the Sackville-Bagginses, besides Sauron, who he utterly hates, they are the closest thing he knows of hatred due to their harassment towards him and his Uncle.
6. Knives. Because he has incurable wound from a blade, they tend to make him uneasy, bringing the memory back — and the pain, as if it were from yesterday.
7. Darkness. Ironic because he has to travel through it, but being in the complete dark makes Frodo highly uneasy because he cannot see let alone prepare himself to hide if there are enemies competent in that setting.
8. The Ring. He hates himself for his attachment to it, and for what is wreaking inside him. He hates it for what it did to Smeagol, and he hates the lives that have been lost trying to keep it, and him, safe.
9. Nosy people. Frodo is undoubtedly the most reserved of all of the hobbits in Tolkien’s literature in a sense, profoundly quiet, and he doesn’t like strangers getting into his generally dangerous business.
10. Sauron. Granted he’s his enemy as Frodo is his, there’s an undeniable hatred of him as there is a great, crippling terror.
