Agincourt and Crecy were infamous for French Knights charging headlong without heed of proper tactics. Likewise, French Knights at Nicopolis ignored the veterans and charged head long into the Ottomans who defeated them. In Haitin, the Crusaders marched against Saladin despite being proven before that a cautious approach was the best counter against the Muslim forces.
The Ottomans even built a tactic around this, where skirmishers would provoke the enemy into an attack on the Ottoman's defensive positions.
Are the examples I listed the norm among knights or was it the exception? Is it really that easy to provoke armies into an attack?
I addressed some of the the myths of French knightly arrogance here. The condensed version of that comment is that quite a bit of heed was taken for "proper tactics" at both Crecy and Agincourt, but various circumstances and the skill of their enemies in these engagements inhibited their plans and led to a break down in command where the plans ended up not being followed. The later mythology of foolhardy Frenchmen charging blindly into the teeth of the enemy developed both from French chronicles attempting to assign blame for their defeats (i.e., the sin of knightly arrogance provoked the wrath of God Almighty) and from later English narratives looking to vilify the French (and, perhaps more importantly, posture their own ancestors as heroic and stalwart salt-of-the-earth Englishmen).
In general, I don't think it would be accurate to describe "knights" as behaving in any uniform way on the battlefield. The reviled yet enduring /r/AskHistorians medievalist caveat that the medieval period was a long period of time and covers a wide variety of cultures and regions. One can dig up as many examples of knights and aristocrats engaging in clever tactics and patient maneuvers that led to victory as one can of knights who made terrible mistakes that resulted in defeat. At both Crecy and Agincourt, the royal English commanders and the rest of their aristocratic brethren were every bit as invested in the knightly culture of their day as their French opponents, yet this did not prevent them from exploiting their advantages and successfully employing a tactical plan to win their battles.