At my current job I do spend a lot of time caring about using the right data structures and algorithms to get decent performance. At my previous job, where per

At my current job I do spend a lot of time caring about using the right data structures and algorithms to get decent performance. At my previous job, where performance was not as important, there were still places where this knowledge was required. For instance, we had something analogous to Google's instant search, where each keystroke in the search box would cause the results to change instantly. Implementing this incorrectly would have caused it to be very slow for the user. I don't ask these questions to separate people with formal education from people without. People with formal education get these questions wrong quite often.