We do a lot of walking (Pennines, UK national trails and European walking holidays) but just cannot get into group walks. We do go out with another couple once in a blue moon, and have sometimes been with groups on guided walks abroad but otherwise just the two of us. The main reason is not inherent anti-sociability (well, maybe me a bit) but because we want to set our own pace, and not be held back by the slowest. It does turn some walks into more of a route march than a stop-start ramble, but there is nothing better than getting into a good rhythm on a ridge or high moor and feel the heart and lungs pumping on the way up and the knees screaming on the way down! I agree about the pub at the end, though!