I never both trimming the spines. A good pair of tongs and fair warning for all dinner guests is all I go for. If everyone's careful about where the handle it and what they pick up first there's no issues.

Dipping sauce = mayo & lemon juice with individual bowls!

Also as you move inward the leaves get thinner. Group leaves together and you can just eat off the entire ends and don't need to scrape against your teeth. Eventually the last group of thin leaves will all come off the heart together. Flatten, dip, and eat the ends.

Don't forget that when you've eaten all the leaves, the fuzzy stuff should be scooped out with a spoon and tossed. That's the only way you get to the best part - the heart of the artichoke!