Along with not inserting a linebreak immediately after a return (which you must learn whether you use semicolons or not), watching out for lines starting with braces accounts for the vast majority of potential ASI errors you're likely to encounter in the wild (in fact, I don't think I've ever been bitten by ++, unary +/-, or a leading RegExp literal), so it's no wonder you didn't see any issues keeping that one, simple rule in mind.