Psalm 16:4 —

The sorrows of those who run after another god shall multiply;
their drink offerings of blood I will not pour out
or take their names on my lips.

James A. Johnston, The Psalms, Volume 1 (Crossway; 2015), page 178 —

Being happy in God starts with saying no. You cannot be happy and satisfied in God if you are riding the fence. Some people wonder why they cannot find joy in Christ, but they have a foot in each world. They want God to bless them, but they are living for themselves too. They hedge their bets.

David knows better. He will have nothing to do with pagan sacrifices. He will not worship by pouring out the blood of their sacrifices, and he will not pray to their gods. Finding joy and satisfaction in God starts by saying no.