There are three main elements that Paul rebukes in this passage: worshiping angels, false humility, and legalism. All three of these practices were common in the church of Colossae as an attempt to become "more spiritual." These attempts were all in vain, though, and these practices contradict what scripture says. As Paul has already emphasized in previous passages, our only responsibility as believers is to be faithful and obedient to God. Christ did the rest of the work at the cross, so striving to meet a made-up ideal negates what He accomplished for us.
Colossians 2:16-23
It can be easy to try to take matters into our own hands, even when Christ has already accomplished everything we need. Are there things you do in an effort to be “more spiritual” that are not founded in scripture?
Think about the early days of your faith. Are there any false teachings that have informed your way of thinking, even subconsciously? Ask God to reveal any beliefs you have that are not founded on truth.