People (I only see women, no idea if it's as prevalent amongst men) who write "Only match with me if you can carry an entertaining conversation" in their bio, then just reply "haha" or ":)" to every message.

People. If every conversation dies out as soon as the other person writes something that isn't formulated as a question, you're the boring one.

I will usually write one or even two questions to get the conversation started. If you at that point haven't asked me anything back, I'll just assume that you have less personality than my refrigerator, and move on to someone else.