Like acids, alkalis are what?
Get a splash of conc. acid (and it WON'T splash in your eye, why not?) on bare skin and it stings.......You wash it off with copious water, not much harm done.
Get a splash of conc. base, and you don't immediately know it. It still is doing damage, but it might be a few hours afterwards that you realize you have a nasty burn. The soapy, slimy nature of bases is responsible for this.