Would you leave it there? Probably not. I imagine you'd tear it off and step on it. There might be screaming involved.
But consider that when you tear it off some blood will fly off. Isn't that bad? The wound would be pretty gross. These are some arguments in favor of leaving the leeches on. Are you convinced? I'm not. I'd still tear off the leech and know that the blood loss and mark would be a small price to pay compared to the total blood loss and the sight of a leech on my leg.
Look at the merits though. Maybe that leech deserves the blood. It's a surprisingly advanced organism. It took a long of work to get on your arm. Look at the ingenuity of it. The ability to hide in waiting. That is patience and persistence. Why should that not be rewarded? That leech was in for the long term. It didn't just bite the first thing in sight such as a rock or your boot.
The leech put in a lot of work too. Did you know it thinned your blood a bit? That helped keep blood flowing. It had to put in work to get those chemicals into your body, and not just any chemicals, these are specific tools and they work very well. Besides, it's to your benefit. Don't you know that that leech is reducing your chance of a heart attack or a dangerous blood clot?
It's time that pansies stopped bashing leeches. They're hard-working organisms just trying to get by. Don't be critical just because they are successful and you're not. Maybe you could take a page out of their book and stop being so lazy and demanding rewards right now.
Let's review the many positive traits of leeches which are overlooked by the masses:
-Patience and persistence
-Settling for nothing less than success
-Talented and effective
-Prevent dangerous health problems
Removing leeches can be harmful. As we can see it's clearly better to leave leeches as they are and shouldn't disturb them in any way. Without them, what would provide an example for personal success?