"Taxes are the price we pay for a civilized society."
- Attributed to Oliver Wendell Holmes.

One may argue, but the epicness of the mustache proves them wrong.

I quite agree, they're definitely a necessity...

I prefer the Slider's theory of time travel. Traveling into the past just sends you to a dimension that looks exactly like the past. So completely screwing up that world would not affect your present or create a paradox where you cease to exist because your father never met your mother.

Be better for the universe if he had never been born
I'd rather build 100 foot tall statues of nude women
That couldn't be any worse than the absurd premise of most religions, but I'd rather worship the Almighty Cheeseburger.
Dude, Kittens are Evil, Evil incarnate
They did, Chuck died.
A better world would have no Rambo movies ever, nor Rocky films.
I tried, they didn't believe me.

observation

Well if we go by the premise of the Abrams films, doesn't matter what you do, observation, voyeurism, tinkering with history, whatever you do the future you return to won't be the one you came from, so the message to potential Time Travelers is, make sure your life insurance is paid up, because you won't be back.

If I could time travel? I'd learn as much as I could about history... experience medieval times, fun stuff.

Then I'd go to the future and take command of a Vesta class MMSE, called the USS Andromeda Ascendant. LOL

Unless you were going back with invulnerable shields and a weapon that never runs out of ammo you really wouldn't like medieval times. The only safe kind of time travel would be where all you can do is observe. A window to view the past is ok, a doorway to interact with it is a really bad idea on too many levels.

Modern Poly-ceramic Armour would be totally impervious to 99% of the dark ages weapons (siege weapons and heavy crossbows)

But the big threat would be Germs not weapons

I'd be most worried about fire.

Because if I suddenly appeared in a flash of light in some 14th century village I'd almost certainly be denounced for sorcery and witchcraft and summarilly burned at the stake.