Alternative form of a camel is a horse designed by a committee

(simile) Extremely rare or scarce.

Alternative form of you can lead a horse to water, but you can't make it drink

(idiomatic) To stop acting in an imperious, overbearing or bossy manner.

One should not unappreciatively question or inspect a gift too closely.

Alternative form of don't look a gift horse in the mouth

(idiomatic) To return to something that previously caused harm.

Enthusiasm of an inexperienced person will cause harm.

(idiomatic) To attempt to prevent a problem that has already occurred.

You can show someone how to do something, but you can't make them do it.