I have to admit to feeling this way myself sometimes. I don't usually take Charlie Brown's tack to resolving it however, because... well, for exactly this reason.
In panel two, compared to the door, notice that Charlie Brown seems very small. There is no way he could reach the door handle. To state it plainly, usually the characters are drawn so they wouldn't have to reach up so far to reach doorknobs.
Made a minor edit....
