Fine because no body else in the history, present or future of the planet has, is or will ever see, hear, feel and think as I do. More than makes up for having a blind spot or two
Imagination can help but it’s tricky. For you to see yourself in real time just as you are while going through life, you need to have a relatively up to date mental model of your body and what it does.
People who do a lot of work on camera are hyperaware of their likely appearance at any given moment because that’s their job.
Bu for most of us, it’s harder because we’re often stuck with a very out of date mental model of how we REALLY look to others.
What adds to the trouble is everybody has their own mental filters that distorts what they see, just as you have yours.
So for example, if you don’t like someone what they look like to you will be negatively distorted. Likewise, a parent really sees their adult children as actual children or an adult child might not notice a parent getting older.
It’s not possible to be prepared for every filter and harder to imagine ourselves as we appear to others but it’s possible.