In my heart of hearts, I knew I wasn't. It's just that some of them seem to be a very easy short cut to producing something edible. Still wouldn't buy them though.
I can't remember the last time I bought a jar of sauce.
I share Mamya's view that they are easy to make and Tilly's concern about the loading of sugar and salt, not to mention other unnecessary ingredients.
I accept that in some circumstances e.g. convalescing and unable to spend a long time standing in the kitchen or wanting to have an introduction to something new then they might have their place. On the whole though I think a quick Google search and starting from scratch is better....and generally cheaper.