I've already put in my 2 cents on nolock... I'll debate something else.

RE the quoted line, do you mean using a hint to force a particular index? If so...

Index hints (and other hints in general) are massively overused. If SQL's not picking the index that you think is optimal, there is usually a good reason why. It could be something like a cardinality inaccuracy that's leading to inaccurate costs, the query could be written in such a way as to make the index less attractive or it could be that the index you think is optimal actually isn't.

95% of the time, the optimiser does actually know best (especially in the later versions of SQL). In those few, rare cases where hinting an index does lead to a performance improvement and the query is written in the absolute optimal way, then document carefully and test carefully and regularly. The index that's good this week may not be so good in a couple of weeks time when the data volumes and distribution have changed.

A query hint is not a suggestion, it's an order. By using them you are forcing the optimiser to do what you say and preventing it from even evaluating plans that may be far more optimal than the one it's actually going to use.

Personally, I've never found it necessary to use an index hint in a real system and in all but one of the cases where I've seen them used, removing the hint improved performance.