Examples in English would be... "live" and "be". You technically should not say "It was
her who answered the door", but instead it would be proper to say "It was
she...". For something more glaringly obvious, consider the sentence "I'm going to live you today"... I hope you are cringing at the violated intransitivity of that verb
In Latin, a lot of verbs that are intransitive (whether they are or are not in English) can take a dative object instead of an accusative. Verbs such as
noceo, nocere and
servio, servire are intransitive not really because of their nature but because of the concepts they express.
Noceo can be thought of as meaning "to harm", but it is really more like "to cause pain"... and you can't just "cause pain someone" because this
someone needs to be an indirect object (i.e. dative) -> "cause pain
to someone". Same thing goes with
servio "to serve" or... "to be a slave to".
There are also some verbs which do not take direct objects because it just wouldn't make sense such as
vivo, vivere "to live", although there are exceptions, such as "vitam vivere", but that is a minor point pertaining to related words. As in English,
sum, esse is quirkily intransitive.
flebile nescio quid queritur lyra, flebile lingua murmurat exanimis, respondent flebile ripae