Sometimes it's hard to find conversation topics when you are with friends. It could be hard to find anything they don't already know, but I think it also depends on the relationship you have with the friends. Today I was with some friends and somehow we always have things to talk about, even if we talk to each other every day. Thinking back I wouldn't even know all the things we discussed anymore, but it's probably our usual topics and we never get bored. It's very nice to have such friends; I feel really comfortable with them.