Order anything on a "bed of leaves" and it's a good bet that 95% your meal will consist of this tastless lettuce gone wrong - which is no doubt very good for profit margins!
Depends where you order it, really.
TBH any self-respecting restaurant will flag up the fact that the salad is rocket, rather than just lettuce, as rocket is more expensive and tastier than lettuce. Good rocket has a lovely peppery flavour that goes extremely well with steak. I grow masses of the stuff for summer salads. It's also pretty good stirred into macaroni cheese.
Iceberg lettuces, on the other hand, are pretty nearly tasteless - all the sensation is in the texture. If you want some flavour and variety, young spinach is a good salad veg, as are young beetroot leaves, dandelion leaves and chard shoots.
Order a generic 'salad' in most British eateries, however, and you'll get iceberg lettuce, a few rings of tasteless tomato and maybe some raw onion if you're lucky. I'm afraid as a nation the British know fuck-all about food and care even less. Most people are happy with a two-for-a-fiver battery chicken deal from the supermarket, oven chips and tinned or frozen veg. The popularity of cookery programmes seems to be in an inverse ratio to the viewers' ability or willingness to cook.