While I agree, the real problem that I have seen is in dealing with Vendor code. You can't fix it without violating the terms of the contract and they refuse to fix it. So now you are stuck with finding ways of performance tuning something else. In one recent case, the best solution came down to adding disk space and short stroking the IO. By reducing the used space from 90% on the SAN down to 80%, we were able to double performance. Granted, that wasn't good enough still - but it helped.