1. Mood Swings: Mercutio notices that Romeo has become moody and erratic. He comments on how Romeo can quickly transition between states of happiness and sadness.
2. Love-Sickness: Mercutio recognizes Romeo is lovesick due to his pursuit of Rosaline. He teases Romeo about being caught in the throes of love and even mocks his language due to Rosaline.
3. Neglect of Friends: Mercutio notices that Romeo has become distant from his friends and prefers to spend time alone or with Rosaline. He expresses concern that Romeo is neglecting their companionship.
4. Melancholy: Mercutio observes that Romeo has fallen into a state of melancholy, which is evident from his brooding and sorrowful disposition.
5. Changes in Appearance: Mercutio comments on Romeo's physical changes, such as weight loss, lack of sleep, and a pale complexion. He attributes these changes to Romeo's love-induced despair.
6. Love-Inspired Dreams: Mercutio also mentions Romeo's vivid dreams, which seem to revolve around his romantic feelings and desires.
7. Loss of Wit and Humor: Mercutio laments that Romeo has lost his usual wit and sense of humor. He remarks on how Romeo's love has made him serious and less playful.
8. Recklessness: Mercutio observes that Romeo's behavior has become unpredictable and impulsive, leading him to make reckless decisions and engage in risky actions.
Overall, Mercutio's observations highlight Romeo's transformation due to his passionate and all-consuming love, which greatly affects his emotions, behavior, and relationships with others.