Sure-fire summer pasta salad

I've been making this pasta salad for years, bringing it to summer barbies and it's always been a hit. It started off as a prawn, mushroom, and avocado pasta salad, but as people's food dislikes were voiced I omitted some of the ingredients. (I haven't got measurements, just go on guestimates).

Dried pasta: penne or fusili (dried is better for salads than fresh)
Creme fraiche or sour cream
Mayonnaise (low fat is fine)
Garlic
Avocados
Lemon juice
Black pepper and salt

1. Cook the required amount of pasta and allow to cool.
2. Mix equal amounts of the creme fraiche and mayo, enough to just coat the pasta, you don't want it swimming in it.
3. Crush a clove of garlic, or two, depending on how garlicky you like food, and mix into the mayo/creme fraiche.
4. Fold the mayo mixture into the cooled pasta, season, and put into the fridge until needed.
5. Before serving, peel a ripe avocado or two (again depending on quantity of pasta) and cut into slices or chunks, then mix the avocado in the lemon juice.
6. Mix the avocado in with the pasta.

Any questions, just ask!