Visible crew/equipment: When Riker approaches his "son" in the prison cell (right after he has discovered the first bluff) you can see the shadow of the mic boom on the back wall quickly moving from the middle to the right. (00:34:40)
![Star Trek: The Next Generation mistake picture](/images/screenshots/353000-353999/353504_sm.jpg)
Visible crew/equipment: When Lt. Chang tells the candidates, "It's unfair that only one candidate from Relva will attend the Academy this year," there are two tape marks visible on the floor between Chang and Mordock. (00:49:00)
![Star Trek: The Next Generation mistake picture](/images/screenshots/353000-353999/353501_sm.jpg)
Visible crew/equipment: When Will is wearing the (unforgettable) indigenous apparel for his meeting with Beata, the moving boom mic casts a shadow on the wall on the right side of the screen. (00:16:25)
Visible crew/equipment: Two white lights reflect off Armus' pool when Picard walks up to it. Since the planet is devoid of all other life, this can only be a reflection of stage lights.
Who Watches The Watchers - S3-E4
Visible crew/equipment: Just after Nuria says "your power is truly boundless" a few seconds later a microphone can be seen dropping and quickly being raised again at the top of the window.
Visible crew/equipment: As La Forge and Crusher leave the bridge, and the camera closes in on Riker, there's a shadow of a piece of filming equipment on the wall behind and to the left of his head, at the upper right of the shot.
Visible crew/equipment: As Picard walks past the display of the ship the lighting rigs, camera and sound equipment are reflected in the panels.
Visible crew/equipment: A boom Mic is visible about nine minutes in, just as Riker and Picard begin walking down the corridor talking about Lwaxana Troi getting married aboard the enterprise.
![Star Trek: The Next Generation mistake picture](/images/screenshots/174000-174999/174763_sm.jpg)
Hide and Q - S1-E10
Visible crew/equipment: When Riker, Dr. Crusher, and La Forge enter the area where the injured colonists are located, the mic is visible for a few seconds at top left of the shot.
Visible crew/equipment: Numerous times in the bridge scenes, the studio lighting rigs are seen in reflections on the work station screens.
Visible crew/equipment: In the opening scene, just before Picard comes out of his room, you can see the shadow of the boom microphone.
![Star Trek: The Next Generation mistake picture](/images/screenshots/354000-354999/354516_sm.jpg)
Visible crew/equipment: While Picard talks to Rasmussen in his ready room, when Rasmussen says, "I can't get quite as worked up as you," it cuts to a wide shot, and there's a white tape mark (T-mark) taped to the floor under the desk. (00:32:45)
![Star Trek: The Next Generation mistake picture](/images/screenshots/354000-354999/354515_sm.jpg)
Visible crew/equipment: On Romulus, when Picard and Data are told, "Eat your soup, courtesy of a loyal establishment," the camera turns to face the duo dressed as Romulans, and an actor's T-mark is visible on the ground behind Data. (00:42:40)
Visible crew/equipment: Boom action is visible in reflections on computer consoles in the back, while Picard and LaForge talk to each other on the bridge. (00:40:15 - 00:40:46)
![Star Trek: The Next Generation mistake picture](/images/screenshots/353000-353999/353635_sm.jpg)
Visible crew/equipment: After the intro, when Garvin tells Gia to go home, Data is standing on the stairs and the actor's green mark is somewhat visible at Data's feet. This green T-mark is clearer when Data hands Garvin the radioactive box he's carrying. Then, when Garvin walks over to the table, there's an orange T-mark on the ground. (00:04:55 - 00:07:40)
Visible crew/equipment: After Gia tells Data to remove his hood, he asks how long it will be until Skoran and the others return. Then, when Data tells her that he must hurry he takes a step forward, and a green tape mark is visible on the floor. (00:36:35)
![Star Trek: The Next Generation mistake picture](/images/screenshots/353000-353999/353545_sm.jpg)
Visible crew/equipment: While Troi tells Riker about the Captain's grueling negotiations between the Gemarians and Dachlyds, when Picard joins them on the bridge, there are three visible T-marks taped to the floor. (00:01:50)
Visible crew/equipment: In Wesley's quarters, when the camera looks at Geordi, there appears to either be a person reflected on Wesley's device or a boom mic shadow plays across it.
Visible crew/equipment: When Dr. Crusher is trying to save the Borg, just before Worf says "lower the force field" a boom mic is visible.
Visible crew/equipment: Numerous times throughout the series, the screws that hold on the panel faces on the Conn and Ops positions are visible.
Answer: He brought the Borg to the Alpha Quadrant and showed them that it was full of worlds waiting to be assimilated. Guinan's homeworld was their first stop, and they assimilated everyone and took over the planet, leaving The Survivors of her race without a home. Q is ultimately responsible for that.
Captain Defenestrator
By the time Q takes the Enterprise to meet the Borg, Guinan already knew who they were and they had already destroyed her world. Therefore the above answer can not be right. I believe Guinan is much more than she appears, and her people have had encounters with the Q in the past. It is these interactions, that obviously were not pleasant, that fuels her distrust.
oldbaldyone
That's what the above answer is saying. Q brought the Borg to the Alpha Quadrant (not Earth) and the Borg destroyed Guinan's home world in the late 2200's, which is why she hates Q. Although she met Q in 2160 and they both saw each other as enemies right away.
Bishop73