Right up there with lemons, for me, are limes.. and in everything from tom yum pa to tortilla soup. That bright flavour of the lemon mixed with a sour tanginess that has a natural affinity with salt, think margaritas..
Guacamole is one of those dishes that benefit from the addition of lime juice for two reasons. First, it enlivens the tastebuds, lifts the lovely waxiness of the avocado and blends with the onion/garlic/salt combination to perfection. Second, it inhibits the (enzymatic) browning of the avocado pulp. Rubbing a little on the cut surface of the fruit and leaving the stone intact will slow down this reaction should you not use the entire avocado.
This almost never happens as I love guacamole on everything from tortillas filled with seared beef and salsa to leftover chicken sandwiches. When I am in the mood for Mexico, this addictive wee condiment adds its unctuous, rich taste and a fabulous shot of colour.