Other obvious anwser (you have same problem with cash, but in that instance I can kick his leg, knock him down, beat the shit out of him and get my cash back along with the tickets for trying to jack me; that doesnt work if i dont know his password on his phone after I get it back from him)
You can always beat the crap out of him, whether bitcoin or not bitcoin. I don't think he would be happy in any case, so you could just let him know in a polite manner beforehand. Though, personally, I don't like either that feature of irreversibility but for more prosaic reasons (you could just make a mistake in the address and your money is gone)...