Griefing attacks in smart contracts involve non-financial disruption, exploiting logic flaws and gas negligence. Common patterns include timing resets, unchecked external calls, and block-spamming loops. Developers should implement safeguards like post-call checks, gas estimation, loop caps, and access controls. Detect griefing using static analysis tools and transaction monitoring. By preemptively addressing these issues, contracts become more robust against denial-of-service disruptions.