my favorite part is how brokerages like morgan stanley don't report the cost basis when they report your sales to the irs, and for no reason I can find.
This means that if you don't report sales from your side so you can note the cost basis, the irs assumes a cost basis of 0 and calculates owed tax on the entire sale value - this applies to stuff like RSU grants as well, and trips up a great many people entering the tech sector ( especially young people who may not have much tax filing experience )
I legitimately don't know why brokerages don't all include the cost basis by default ( or why they aren't required to by law )