The auto-generated titles on the left-hand side in chat are high-level/not always intuitive (especially if you have chatted about multiple similar topics recently), which makes it difficult to locate past conversations. This is compounded by the fact that the search function for recent chats only searches against the auto-generated titles, not the content within the chats themselves.
Being able to manually rename chat titles (or having search cover full chat content) would make it much easier to find and revisit previous conversations.