Well with regard to the tiger reference, fear was very useful in prehistoric times. if you weren't afraid when a mammoth was going to eat you, you died. Your genes were wiped out and only those who were fearful lived. Their genes were passed on. Lets pretend I said an artic saber toothed tiger.
The same fear is present whenever we do a presentation, go out on a date, or do an interview. But its a redundant, useless fear. Our brains actually think that we are in a life-threatening situation, that we are faced with a tiger, its what evolution has wired us to think. Fear is useful when we want to run, for example If I'm a teenager and I throw an egg at a house and the cops arrive, it's good that I'm afraid so I can peg it. But its only really good in terms of knowing when to run away. To be honest, I havn't been in that many life-threatening situations, and a tiger hasn't chased me in a while. I've had to deal with interviews, dates and presentations much more regularly, where I could have done with a good dose of fearlessness.
Of course fear may be useful in certain situations. But its too prevalent. Ask Muhammad Ali would he rather have been safe and lived in fear as opposed to being fearless. Better to die brave than live a coward.
On that note take the gram of phenibut. Taking it in 100mg increments is pointless, you simply won't make any progress doing things that slowly. Unless you have serious medical conditions just do it, I can't really see a worse case scenario, you don't really react well, you have a bad day, then you stop taking it and are much the wiser for it and can move on to try a gram of the next substance that may work for you.
Fortune favours the brave:)