Going to the concert alone means you pick where to stand, when to leave, and who to talk to.

Doing something alone removes the negotiation that usually shapes an evening, and what is left is entirely your own. There is a small social cost at the door and then it disappears, because nobody in a crowd is auditing who came with whom. Waiting for company is how most people miss the thing entirely.

Buy the single ticket for the thing you want to see. Go early, stand where you like, leave when you are done. You will find you are far less conspicuous than you expected.