How does unplanned food eating come about for you?

When you find yourself eating when you had not planned to, was it because:

• You were bored and before you knew it, there was a snack in your hand.
• You were going through the day and someone gives you food, or invites you to lunch or dinner, etc.
• You are going through the day and come across food that is just available and you get hungry, such as free samples, food giveaway, free and open buffet at the museum you happen to be at, etc.

When you find yourself eating and think, why am I eating, I did not plan to eat now, how did it happen, or how does it usually happen?