To show the effect that lag would have in real life, broadband provider ume.net did a series of experiments with the Oculus Rift (now owned by Facebook...so RIP). Participants were given a VR headsets and asked to do a variety of seemingly simple tasks made frustratingly difficult with the addition of a delay. The results are interesting and pretty funny. It's also a very effective piece, so kudos to the agency involved (couldn't find a link). View the site here.