For starters you don't want to be casual about 110 volts [0] and for seconds the systems that control heart rhythm use electricity. An electric shock can cause a heart to just stop some hours later (happened to a family friend as far as we can tell).
It is invisible, can kill and humans don't have the right nerves for pain to be an indicator of how bad the damage is. Electricity is hazardous and work on it should leave no scope for surprises.
[0] https://www.asc.ohio-state.edu/physics/p616/safety/fatal_cur...