Wait till you need to use a formula which has somewhat complex uses of indexes like 2^(2n+1) and see how having deal with them in 1-base indexing in addition to

Wait till you need to use a formula which has somewhat complex uses of indexes like 2^(2n+1) and see how having deal with them in 1-base indexing in addition to 0 based indexing makes it add bit of unnecessary confusion.