Fools should be avoided at all costs. And just so you know what a fool looks like, the book Proverbs provides a very clear description so that you can spot a fool and avoid them and the destruction they cause:
A fool is unteachable because he will only listen to himself and those who agree with him (Prov. 12:15). The fool will not listen to God (Pro. 1:7), to parents (Pro. 15:5), or to wise, educated, and informed people (Pro. 15:12). The fool will not learn from his mistakes (Pro 26:11). In fact, the fool refuses to listen (Prov. 13:1; 15:12) and attacks any who try to correct him (Pro. 9:7-8) Sadly, A fool takes no pleasure in understanding, but only in expressing his opinion (Proverbs 18:2 ESV).This is because fools do not seek knowledge and understanding, but rather he feeds on folly (Prov. 15:14).
A fool is uncontrollable. A fool cannot control his mouth (Pro. 10:8,10,14). His words are folly (Pro. 15:2; 13:16), rash and hasty (Pro. 29:20), and filled with lies and slander (Pro. 10:8). The fool is big on words but small on deeds (Pro. 10:8,10). The fool cannot control his emotions (Pro. 12:16), his anger (Pro. 14:16,29; 29:11), or his impulses and appetites because he despises discipline (Pro. 1:7).
A fool enjoys his sin (Pro. 10:23) and will not give up his foolishness, regardless of how destructive it is (Pro. 26:11; 27:22). Strife, quarrels, and insults are his stock in trade (Pro. 22:10).
A fool is proud and arrogant (Pro. 21:24; 28:26; 26:12). Because fools are proud and arrogant, they like to meddle and stir up controversy. They are argumentative and combative. Their pride and foolishness create problems and brings sorrow (Pro. 10:1; 11:29; 15:20; 17:21; 27:3). It is better to meet a bear robbed of her cubs than a fool in his folly (Prov. 17:12).
A fool places no value on wisdom, no value on discipline, no value on the moral life. The fool is his own authority. Correcting a fool is pretty much impossible and his normal pattern in life too not receive correction. If something goes wrong, it is because someone else “blew it.” If his plans fail, it is not his fault: He is the victim of someone else’s corruption or incompetence. He’s a blamer. He repeats the same mistakes and failures over and over, and rather than changing he blames his failures on others. Yet, the reality is the fool suffers because of his own choices (Pro. 9:12).
A fool has so blinded himself with his arrogance and folly he cannot find wisdom even when he seeks for it (Pro. 14:6; 24:7). After all, he will not concentrate on wisdom (Pro. 17:24) but thinks he can just buy his way out (Prov. 17:16).
A fool squanders his resources (Pro. 21:20; 29:3; 14:24; 19:10) and cannot be trusted with responsibility (Pro. 26:1,6,7,8,10). Eventually, his foolishness will be revealed in full display and he will be detested by all (Pro. 24:9).
So, do us all a favor, if you see a fool, avoid him at all cost. And by all means, do not hire him to do a job or entrust him with any responsibility (Prov. 26:10). If you made the mistake of hiring or befriending a fool, cut your losses, and move on.