3.23 USAGE NOTE

Note that even verbs which are almost always followed by a direct object can occasionally be used intransitively. This is possible in very restricted contexts. For example, if you are contrasting two actions, it is not necessary to say what else is involved.

If you use a list of different verbs for emphasis, you do not need to name the object.

If you repeat a verb in order to contrast it with a similar action, or to emphasize it, the object can be omitted.

3.24

Verbs which describe feelings and attitudes can sometimes be used without an object, particularly in the 'to'-infinitive form. This is because the object is assumed to be people in general. For example, 'please' usually requires an object, but you can say 'He likes to please', meaning he likes to please people.