Reversible quotations

Walking around the Imperial War Museum today, I saw this quote:

"Mankind must put an end to war, or war will put an end to mankind." -- John F. Kennedy

I realised that this kind of quote, which I'll call a "reversible quote", is pretty popular. But all you really need to do is sit down and think of two concepts (i.e. "mankind" and "war"), join them with a verb (i.e. "end"), and then reverse it. Or, for another form, think of a verb (i.e. "fail") and a noun that can also be a verb (i.e. "plan"). Here's a few other quotes I found. I'm sure there's lots of others, feel free to suggest them and we can create a master list of reversible quotations.

"And so, my fellow Americans, ask not what your country can do for you; ask what you can do for your country." -- John F. Kennedy

"Let us never negotiate out of fear. But let us never fear to negotiate." -- John F. Kennedy

"A pessimist is one who makes difficulties of his opportunities and an optimist is one who makes opportunities of his difficulties." -- Harry S. Truman

"And in the end it's not the years in your life that count. It's the life in your years." -- Abraham Lincoln

"For those who like this sort of thing, this is the sort of thing they like." [eh?!] -- Abraham Lincoln

"Peace is not absence of conflict, it is the ability to handle conflict by peaceful means." -- Ronald Reagan

"He who fails to plan, plans to fail." -- Unknown

It's not exactly a reversible quotation, but I couldn't resist:

"I just want you to know that, when we talk about war, we're really talking about peace." -- George W. Bush

This all looks pretty easy to me, so I'm inspired to try some of my own:

"A photographer may think he is taking a photograph of a place, but really the photograph is taking the photographer... places." -- Tim G. Jones

Okay, so it's not that easy. Let's try again using the second form. > He who prizes the win, wins the prize. -- Tim G. Jones

See? Instant eloquence guaranteed. It doesn't even need to be true.