A frustratingly not-terrible action thriller.
"Bad Influence" is like one of those old Charles Atlas ads, where the bullies on the beach kicked sand into the eyes of the 99-pound weakling, until Atlas came along and showed the wimp how to build some muscle. The primary difference between the ads and this thriller is that the role of Atlas is now filled by a sadistic sociopath. He walks into the life of a cowardly financial analyst and treats him to some assertiveness training that is more than he bargained for.
The analyst is played by James Spader, whose cool diffidence is just right for the early scenes, in which the office bully hacks into the computer system and hides three months' worth of Spader's work. In response, Spader does what any normal coward would do: He walks across the street to a bar to have a beer. It isn't his day. In the lounge, a big guy is having a fight with his girlfriend, and when Spader looks at him wrong, he gets his face mashed into the bar.
That's when Rob Lowe comes in, breaks a beer bottle off at the neck and has a few words with the bully while waving the jagged edge at his face. The bully leaves. Spader is grateful, and over the next few days he becomes friends with this mysterious stranger, who offers to teach him how to stand up for himself. At first the lessons are innocuous, as Spader outsmarts his rival in the office. Then they get more troublesome, and finally they get deadly.
"Bad Influence" reminded me a little of "Strangers on a Train," the 1951 Hitchcock movie where Robert Walker offers to trade murders with Farley Granger - his father for Granger's wife - so they can both be rid of people they hate. Granger doesn't take him seriously, but Walker is very serious indeed. In "Bad Influence," Lowe has the smooth Walker role, but the difference is Spader has no idea he has made a bargain until it's much too late.