How do you make your mayo, and do you make a good ranch dressing?  Two things we run out of all the time.
Mayo is simply an emulsion. 
    1 large egg yolk
    1 1/2 teaspoons fresh lemon juice
    1 teaspoon white wine vinegar
    1/2 teaspoon salt plus more to taste
    3/4 cup canola oil, or grape seed oil divided.   You could even use EVOO for more flavor.
Whisk the first 4 ingredients and pour into a blender.   Pour oil VERY SLOWLY while blending, until the desired consistency is reached.
Ranch.
    Â½ cup mayonnaise
    Â¾ cup sour cream
    Â¾ cup buttermilk
    1 Tbsp white wine vinegar
    1 Tbsp lemon juice
    1½ Tbsp Worcestershire sauce
    2 tsp chopped parsley
    2 tsp chopped chives
    1 clove garlic, crushed
    Â½ chopped scallion
    1 tsp mustard
1. Add all ingredients with about half of the buttermilk to a blender. Puree for about 10 seconds to combine. Check the consistency and add additional buttermilk a couple tablespoons at a time if you desire a thinner dressing.
If people would make their own dressings, they'd never buy Seven Seas, again.  All you need for a  vinaigrette, is an acid(lemon juice, vinegar, etc.)and a fat(canola, grape seed, or EVOO)  I like to take a garlic clove, crush it in a metal bowl with a fork and some salt(about 1/2 tsp)  whisk in lemon juice and whisk in the oil.  Add parsley and salad greens, toss.  
Awesome.