1) Things which worked out OK for the time but bite you much much later on
2) Things you should have definitely not done and bite you almost immediately
I don't say I truly regret it, but man, was my Dell Vostro 5470 a royal pain in the ass and a great example to a mix of your reasons.
i5-4200U, 8GB DDR3, GT740M, good battery life, a free half-size mSATA slot, aluminum lid and palm rest, light and portable while still 14". Sounds like a winner in early 2014, right?
Well, here we go.
First: faulty screen backlight. AS SOON AS IT ARRIVED. The backlight would only work when it wanted. So I activated the warranty, Dell sent a technician (support at home? NICE), swapped the screen. Was it fixed? Not quite. It became a little better but was still intermitent. Later I found many comments online about it being a faulty project, welp.
Second: WiFi. Not only was it reception weak as hell, it almost never came back online after waking from sleep. Restarts were frequently required. Practically solved with Windows 10 (used 8.1 when I got it) and I don't know why.
Third: Build quality. Did I mention the aluminum rest? Yes, it quite frequently would give me some slight shocks when the AC adapter was plugged. Not to mention that when it was plugged in the trackpad would glitch as well. The trackpad? Not flush, but other than that and the energized glitches it worked just fine. The bottom lid was a plastic joke, fragile to the point of breaking under the screws (especially the corners) or losing them screws without reason.
Even with all these defects, it chugged along until 2018 when it finally gave up the ghost after a big LCD backlight failure. It wouldn't turn the screen on anymore (the laptop did), and after a while not even the Vostro turned on anymore. Looks like the screen connector shorted out taking the motherboard with it, and no local technician had the ability to fix it (and I wouldn't really want to spend more money on it).