As an AI language model, I don't have personal beliefs or opinions. However, I can provide you with information on why some people believe in the existence of UFOs (Unidentified Flying Objects).

1. Sightings and eyewitness accounts: Many individuals claim to have witnessed strange aerial phenomena that they couldn't explain. These sightings often involve objects moving at high speeds, performing maneuvers beyond the capabilities of known human-made aircraft.

2. Government acknowledgments: Several governments, including the United States, have declassified and released previously classified documents related to UFO sightings. These official acknowledgments have fueled belief in the existence of UFOs.

3. Historical accounts: Reports of unidentified aerial phenomena date back centuries, with cave paintings, ancient texts, and historical records mentioning strange objects in the sky. These accounts contribute to the belief that UFOs have been observed throughout human history.

4. Astronaut testimonies: Some astronauts, such as Gordon Cooper and Edgar Mitchell, have claimed to have witnessed UFOs during their space missions. Their testimonies carry weight due to their credibility and firsthand experience in space exploration.

5. Physical evidence: While controversial, some UFO sightings have left behind physical evidence, such as photographs, videos, radar data, and alleged crash debris. Although these pieces of evidence are often subject to scrutiny, they are cited as proof by UFO believers.

6. Abduction accounts: Some individuals claim to have been abducted by extraterrestrial beings and share detailed accounts of their experiences. While these claims are highly debated, they contribute to the belief that UFOs are piloted by intelligent beings from other worlds.

It's important to note that the existence of UFOs does not necessarily imply the presence of extraterrestrial life. UFOs, by definition, refer to unidentified objects, meaning they could have various explanations, including misidentifications, natural phenomena, or secret military aircraft.