I wish/If only + Past perfect I wish I had come to your party! I wish I had worked harder. If only I hadn’t eaten so much. If only I had driven more carefully.I should have (not) + Past Participle I should have come to your party. I should have worked harder. I shouldn’t have eaten so much. I should have driven more carefully.I regret +Noun/V-ing I regret not coming to your party. I regret not working harder. I regret eating so much. I regret leaving you alone.