And if your answer is to find happiness in retirement that's justfiable but realize the quicker you find happiness the quicker you can feel "retired" even if you still show up to work everyday.

House Hacking will prob not make your cost of living $0 in the Bay but you can get ~70% of your living costs covered thus giving you the cash to either pay the property down quicker, have some financial freedoms or whatever!

The more intentional time you spend here, the quicker you will learn and connect with people who will help get you on down the road to success.

If you are able to pay it off right away and start throwing money in your savings account for the flip project in the near future, you will be able to build cash that much quicker to put that money down and it will free up cash to help you pay for holding costs of the flip if you need it. 

Based on your argument for "quicker" money what would be the reason investors buy $100,000,000 office buildings in San Francisco at 5% cap rates (where there are actually analyzed cap rate comps)? 

I love that REI offers the opportunity for reaching FI quicker due to leverage and rents, but I don’t want to lose my shirt, either.

That way I can give them more money that I'd otherwise be giving to the bank, we can close quicker, and they don't get hit with a huge capital gains bill.

Refinancing (without pulling out equity/changing your rate) does nothing to help you pay it off quicker. 

Most seller's like to be able to get cash quicker so build a good relationships and be a problem solver.  

Getting rich quick means GOING BROKE quicker.