Usually it's something like you have a sports event you want to see, head to the pub, and you're sort of half watching it on the TV, and there's others around w

Usually it's something like you have a sports event you want to see, head to the pub, and you're sort of half watching it on the TV, and there's others around watching the same thing or chatting. If people are talking about something a little ways away from you it's socially acceptable to butt in, more or less. As you spend time in a local, you also get to know the regulars and they'll wind up introducing you to other regulars, etc. Double all this if there's more affiliation going on, like you're all immigrants or ex-pats or whatever, or if you're all lawyers or something. Source: Irish immigrant family.