Why Critical damping is often the goal of Mechanical engineers in designing systems?Fig: A Damped Oscillation
From figure it can be noted that amplitude decreases exponentially which is the case for a damped oscillation,

A undamped oscillation isn't acted by any opposing force meaning it oscillates indefinitely.

But a damped oscillation is acted by another opposing force of damping constant b which is what we see in our daily life.

where,tau is damping time constant that is the time taken to decrease exponentially by 1/e of its initial value and

Since, the mechanical engineers doesn't want unwanted and...