Анекдот №130754

есть правило, нет правила...

Вот, к примеру, на http://www.chompchomp.com/terms/infinitive.htm:

...An infinitive will almost always begin with to. Exceptions do occur,
however. An infinitive, for example, will lose its to when it follows
certain verbs. These verbs are feel, hear, help, let, make, see, and
watch...

Мимоходом