According to Jewish law there are three modern veggies which can be used as the "bitter herbs" which ritual dictates that we eat. The three are lettuce, endives, and horseradish.
In the New York community in which I grew up there was only one. Horseradish. For some reason, the old geezers at the seder meal saw it as a sign of male pride to demonstrate the ability to swallow the painfully hot stuff.
In Israel it came as a shock to discover that horseradish is only an Ashkenazic tradition.
I don't buy the commercial stuff that comes in jars.
I grind my own.
Just grind up the killer root (pictured below). Mix with water and vinegar and add a pinch of sugar and salt. Stir it, spoon it into a bowl, cover the bowl with plastic wrap, and pop it into the fridge. The next day uncover the bowl and spoon the horseradish into screw-top jars.
A really simple process. The only problem is that the grinding of the horseradish produces fumes with the power of tear gas.
For a weaker mix grind up some beets and then add some of the pure stuff.
At our seder this year I and the other men calmly assured each other, through tear-streaming eyes and between fits of table-pounding anguish that the hazeret (Hebrew for horseradish) was not too strong for us.
I've become one of the geezers.