It kind of depends on the activity for me
certain things, like going to a bar, movie, concert are pure social events and are best done in small groups I think, that way you don't look like the lonely drinker and small groups are still approachable by other small groups, so new contacts are possible.
Other activities are best done either alone or with some other person that shares the interest in the subject to accompany you.
like for example: going to an art exhibition...
Other than that, I enjoy solitude from time to time, gives me time to think, enjoy the things I alone like, have some quality ME time
