Answer:
If you break me, I do not stop working. If you touch me, I may be snared. If you lose me, nothing will matter.
It is the great nemesis of the lactose intolerant.
Youโll have me at night and if you remove the first letter I denote the top, such as on a train
I have a neck but no head. I have a body but no arm. I have a bottom but no leg.
I drift forever with the current down these long canals theyโve made, Tame, yet wild, I run elusive Multitasking to your aid. Before I came, the world was darker, colder, sometimes, rougher, true. But though I might make living easy, Iโm good at killing people too.
Almost everyone needs it, asks for it, gives it. But almost nobody takes it.