心 is one of the most productive radicals and components in Chinese. It appears in hundreds of emotion and thought words: 想 (think), 感 (feel), 意 (meaning), 忘 (forget), 怕 (fear).
usage
Common compounds: 心情 (mood), 关心 (to care about), 小心 (careful), 开心 (happy), 放心 (relieved), 中心 (center).
