It's true God wants us to love others, even if they aren't particularly loveable. Jesus said, "Love your enemies and pray for those who persecute you.... If you love those who love you, what reward will you get?... Do not even pagans do that?" (Matthew 5:44, 46-47).
The key is to understand that God wants us to treat others the way He has treated us -- not because we deserve it, but simply out of His mercy and grace. Are we loveable in God's sight? Do we deserve His love? No, not at all -- not if we're honest. At best, we've ignored Him and treated Him as if He didn't exist; at worst, we've deliberately rebelled against Him and done everything He doesn't want us to do.
And yet God still loves us! He loves us so much that He sent His Son into the world to give His life for us. God didn't wait for us to clean up our lives or become perfect; He reached out to us in spite of our sin. The Bible says, "But God demonstrates his own love for us in this: While we were still sinners, Christ died for us" (Romans 5:8).
As your family gathers, ask God to help you see them through His eyes, and with His love. Pray for them -- not only that they won't be obnoxious, but that they'll sense Christ's love through you. In addition, ask God to help you plan activities that will keep them occupied, and even enjoying each other.