One might try and think of our Universe as just a big version and variation of "Star Trek's" Holodeck but programmed from the outside like a computer simulation or a computer / video game. How so? Here are eight possible reasons why.
*Probability. The Reason: Really real reality is a one-off / a one-and-only. Really real reality can however contain multi-millions / billions of virtual realities / simulations. Place your bets.
*The Accelerating Universe (and associated notation that the energy density of the Universe remains constant thought the Universe is expanding). The Reason: This implies a free lunch / getting something from nothing. Simulations can of course create this illusion.
*The "Observer Effect" (especially the delayed Double-Slit experiment). The Reason: There's no known, natural, or rational explanation or mechanism apart from introducing virtual reality's special effects.
*Radioactive Decay. The Reason: No causality. Again, this is an illusion, a special effect that can be programmed into computer software.
*Mathematical Equations. The Reason: If you were to ask one of our video game characters what their ultimate reality was, they would, on reflection, and being smart little buggers, have to answer "mathematics". Now fast-forward to your reality, which is ultimately what? Mathematics. All of physics - the bedrock in thinking about and describing reality - is describable as or in mathematics. Now the really interesting thing is when you examine the mathematical equations that describe the laws, principles and relationships of the physical sciences, against all expectations, the exponents and coefficients nearly always tend to be low value whole numbers and simple fractions. These equations are not human inventions. Mother Nature dictates what they must be - or perhaps they are written into the software that determines those laws, principles and relationships of the physical sciences.
*Fine-Tuning. The Reason: Now it is not enough to design and give properties to each of the bits and pieces that collectively make up the Standard Model of Particle Physics. They have to be fine-tuned to fit together. Just like Lego Blocks, you can intelligently design thousands of types of Lego Blocks, but if they can't or fail to snap / fit together then what's the point? Simulations and the software that programs them into existence have to be fine-tuned in order to make any sense of the simulations in and of themselves.
*Mind - Body / Brain Dualism. The Reason: The physical is affecting the non-physical and vice versa. This defies common sense as well as any sort of explanatory mechanism. Again, one can call on special effects to create this illusion.
*There's also the category of things seen but always elusive and never substantiated: ghosts; UFOs; Bigfoot / Sasquatch; Loch Ness Monster (and other lake / sea monsters). They tend to all fall under the category of "It can't be therefore it isn't" versus "I know what I saw". The reason for the paradox: This contains inherent inconsistencies and contradictions. And there are numerous examples as suggested above: UFOs, alien abductions and ancient astronauts; mind over matter from ESP to telekinesis to remote viewing to the placebo effect; accepted miracles (by the Catholic Church for example); supernaturally themed visions; ghosts, hauntings and poltergeist; phantom objects (i.e. - trains); anomalous disappearances; OBEs (Out of Body Experiences) and NDEs (Near Death Experiences); past lives and reincarnation; alternative medicine from copper bracelets to acupuncture to use of crystals to the power of positive thinking; the wee-folk like leprechauns, elves and fairies; the not so wee-folk as in the Amazons or those Biblical giants in the earth as well as Goliath; and one should honestly also include quantum physics here. There almost seems to be way more things to disagree on than agree on. However, as you would be well aware, Hollywood's special effects can create all sorts of things that can't be yet things that you see!