The mayonnaise I tried making myself today (first try ever) wasn't entirely bad but there was something off-putting to the taste too, as if eating a spoon of pure oil. Now if I had never had store-bought mayo I would think that's normal, considering that by far most of what goes into making mayo is pure oil. But I don't recall experiencing a similar off-putting taste in any store-bought mayonnaise, including the one I have in the fridge at the moment. So why is it that mayo (at least store-bought) doesn't seem to taste like pure oil?
My current hunch towards explaining this (after some Google'ing) is the following. Mayonnaise is an emulsion of a large amount of small drops of oil in a small amount of something watery (vinegar, lemon juice, …). The bigger the drops, the more the mayo still resembles pure oil, and hence tastes and feels like it in your mouth. Conversely, the smaller the drops, the less it resembles pure oil and (for some reason I don't understand) it tastes different or just gives a different mouth feel. Does that make sense? It would mean that next time I try to make mayonnaise I should whisk it more vigorously to get smaller drops of oil? Does that mean mayonnaise is better if you make it with a blender, as it's easier to get smaller drops?
I also considered it might be that I just don't like the taste of the oil I used ("salad oil", the fine print says it's "100% canola"). But I don't think that's it, considering that another store-bought mayo which I like is also made with canola oil (found the ingredient list online, the store-bought mayo I have in the fridge right now is another brand which vaguely says "vegetable oil" in the ingredient list).