These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Fridge Brilliance: Hitch actually does exactly what he early claimed he does for Albert. His pitch involves telling the men to be themselves ("If you're confident, be confident. If you're shy, be shy") and as he said to Allegra earlier in the scene, she never would have noticed Albert if it wasn't for him. This is only a shocking revelation to Hitch because, as he was called out earlier, he doesn't believe his own pitch.
Fridge Horror: After Hitch's story is printed in the paper, we see one couple approach him, the woman suspicious that her boyfriend used Hitch's services to hook up with her. How many other perfectly happy couples across the city do you think are likely in the exact situation, and you know that not all of them are going to resolve it peacefully.
Funny Moments: Several, most notably Albert's dancing prowess and Hitch's food allergy incident. The end credits feature the entire cast dancing insanely at Albert and Allegra's wedding.
Strawman Has a Point: The title character makes some very valid points about continuing with one's life, adapting, and moving on after a relationship goes sour. He gets called out on this by one of his clients who outright calls him a coward for not chasing after one's love; granted, in the client's case, the breakup was because of a misunderstanding, but on Hitch's case there was a very clear and valid reason for it. As expected, since the film is a Romantic Comedy, Hitch gives in and goes great lengths to get back his love interest even after several rejections, incurring extreme behavior and injuries to himself. Try imagining how that would work in Real Life.
Why Would Anyone Take Her Back?: By the end of film, Sara has almost ruined Hitch's career, publicly humiliated Allegra and Albert and nearly broke them up as well, and as Fridge Horror explains there's no telling how many couples around New York may be split up over paranoia the man of the couple had help from Hitch. She also did all this without ever trying to get the facts about Hitch or asking for his side of the story. Yet, Hitch forgives her and begs her to take him back.