The most common reasons a player gives not to serve & volley plus corrective corrective measures.
I: My serve is too weak - the very nature of playing serve & volley tends to force a player to throw their ball toss farther in front to create a "leaning effect." Waiting behind the baseline to make sure your serve is in is the real killer - always assume your serve is in and be on your way to the net.
II: I hate the "lob" return off my serve - fear of the "lob" return is usually caused when the server is moving toward the net at an out-of-control speed. They are moving so fast they cannot stop and go back to track the lob over their partner's head.
III: I don't feel like I am fast enough - an interesting note in serve & volley is that you only need to be fast in doubles for 5 or 6 steps. Consider this speed the speed you would have on a super highway - tennis is a game of short bursts of speed.
IV: I hate the wide angle return of serve - fear of the "wide angle return" is usually caused by a player not "reading" their opponents racket. After they move in their 5 or 6 steps (called a split-step) they stay there too long, thus giving their opponent too much angle.
V: The ball is always at my feet - this excuse can be attributed to (a) your serve being not deep enough or forcing enough; (b) failure to read the opponents racket; (c) not taking your first 5-6 steps fast enough; or (d) standing still too long near the service line and waiting for the ball to come to you - go to the ball!