"Let everything that has breath praise the Lord! Praise the Lord!"
Psalms 150:6 ESV
Everything that has breath should be using it to praise God for He is worthy of all praise.
Praising the Lord should not be conditional based on our own feelings or circumstances. God is to be worshipped and praised in all circumstances because of His unchanging and awesome attributes.
Psalm 150:2 says to "Praise Him for His mighty deeds...". The works God has done in His Word are to be reflected on to which He should be praised for.
There are countless reasons to praise our Lord, however let us remind ourselves that should not be conditional. Let us praise Christ because He is worthy of all our praise.