Re: Hard/impossible starting
It sure is,
But think back to say around the 60's or so when most engines had mechanical lifters. On mechanical lifters, you had to use a feeler gauge to set the distance between the tip of the valve stem and the rocker arm, A.K.A lashing the valves. This is to be sure the valves would both have the opportunity to completely close, and also keep the rocker noise to a minimum.
OTOH, hydraulic lifters are set to zero lash. In other words, the components of the valve system are constantly in contact with each other. The lifter is acting like a buffer, both allowing the valves to completely close, and keeping the valve train noise to a minimum.