This pattern is used to state what you think or believe. It's a common way to soften statements or express personal opinion, rather than stating facts. The subject is usually 'I' (watashi), but in questions it can be 'you' (anata). When quoting your own thoughts, the particle 'to' functions like a quotation marker, similar to 'that' in English.

In casual conversation, you'll often hear と思う (omou) in present tense for your current opinion. For past thoughts, you'd use と思った (omotta). When you want to express a thought about something that hasn't happened yet, you often use と思っている (omotte iru) to indicate you've been thinking about it for a while, but と思う is fine for immediate opinions.

Note that in polite speech, you might use と思います (omoimasu) instead of と思う. The dictionary form と思う is more casual and used among friends or in informal writing.