Onions are an ingredient in almost every recipe. I hate the taste(flavour) of them (I know I might be the only one). I always try to avoid eating them and try to pick them out of the food. Seeing that I am the only one in the house that doesn’t like the taste of onions not using them in a recipe would be selfish.   I was just wondering (a) if there would be a good substitute or (b) do I really need to have them in a recipe? And (c) what purpose do they add to food?  
As a child, I used to hate the feel and taste when I conciously bit on a piece of onion (strongest offender: medium-sized chunks, sautéed glassy but still firm). Sometimes that still happens.  However, I use onion a lot myself now in cooking. Lots of dishes really need the kind of taste onions can supply; even though that taste may by itself be a bit gross, it's really useful in the mix. (This is true for many other ingredients as well!) I can only speak for myself, but very likely, there are some dishes where you don't even notice that onions are in, but they are – and you wouldn't like it if they weren't!  Do use onions, just do it consciously. There are broadly three ways of preparing them that I consider effective, each suited to different cases:   Disperse them throughout the dish. Either chop them really fine and sautée (with the right technique and a decent knife you can get the chunks down to only a few millimetres), or boil with other vegetables and then purée. You'll get all the good taste, but nowhere too strong and without any unpleasant mouth-feel.Ideal for light/creamy sauces or soups. Caramelise them boldly. Frying changes the taste of onions a lot, it makes them much sweeter, gets rid of the pungency in exchange for a really concentrated savouriness, and almost completely tames the consistency. Browned onions play great together with strong seasonings like garlic and pepper, as flavouring for chewy mushrooms or meats. Or the opposite: keep them mostly raw! The freshness and crunch of raw onions can also be very useful without evoking what I call the bad onion effect – albeit in a completely different way. Thinly sliced in salads, or very quickly stir-fried in rice dishes, you keep the raw pungency in check while staying clear of the uncanny softness. Again, it's a good idea to define the taste heading with other sharp flavours: vinegar or chilies work well.   Perhaps you won't be able to befriend yourself with all of these preparation methods, but you should give them a try. 