A very holy priest wrote to me yesterday with a simple reminder I can share with all.
If something or someone brings us closer to God and helps us to grow spiritually in perfection, then we can pursue that thing, or be friends with that someone.
If someone does not help up grow spiritually and if something draws us away from perfection, we need to avoid such a thing, such a person.
Simple.
Also, one must always be on guard against the wiles of the devil. Something, or some person which may seem good and true may not be so.
When in doubt, go to Mary.