S42 vote coming in.
Good light, quality is excellent, just the UI is horrible.
Even trying out the other ui’s wont help? I love all 6 of my meteors!
I’m going to add almost every niwalker I own. Parasitic drain. Can’t just load it and leave it in the car or bag. Tailcap doesn’t lock out. Same with the Olight x7, and my s6330 which has parasitic drain in ONE slot! I can’t win…
I love my Nitecore Tini and hate it at the same time.
I love the format. I love the low weight. I love the beam. I love the output. I love the battery capacity. I love the rechargeability.
I don’t like the looks. I don’t like the cheap plastic lining with silvery finish that peels off.
I hate the UI. The slow turn-on is bad. The demo mode drives me nuts.
It’s on my neck. Largely because it has no real competition in its size/performance class. But sometimes when I can’t stand the Tini I switch to DQG Hobi.
That’s one reason I got the copper TINI
That’s another great light that shouldn’t be hated but is 
BTW, I love the Tini
Anything Manker (almost)
Manker makes fine flashlights with great efficiency and innovative concepts, but the looks are not my taste at all, too round-ish, too much going on, I like simple straight designs.
That kept me from buying many a Manker.
Also the press-&-hold-to-on\off for me. That is an instant dealbreaker.
I love Manker MK34 but hate tint, Manker’s UI & 21 seconds time stepdown from turbo. That is why I got XPL-HI 4000k MK34vn from Vinh. Problem solve!! I still like it better than my new Fireflies ROT66 XPL-HI 5000k.
I am predisposed to dislike a rosy tint applied to a white wall. (It should look white, right??)
Even my XP-L HI V2 3A 5000K Rot66 and D4S add a discernible tint to my Navajo White walls. (peach sorbet be danmed)
My D4S XP-L HI V3 1A 6500K does not, and appears much closer to what I see with sunlight through my window.
Mine eyes have seen their glory and need correction at reading and computer distances butt nothing else so far.
Fenix E01.
Yes, I know it’s indestructible. Yes, I know it will use a battery until the last molecule of electrolyte has reacted. But I just can’t abide that misshapen beam with its nasty purple tint.
I also find myself having less and less patience with twisties (but’s that not unique to the E01).
My Fenix UC35 was a great light. Then I discovered neutral white and high CRI. And then I started wearing gloves whilst out and about.
I can’t stand the cool white low CRI LED in the UC35 any more, and the side switch to change modes is so low-profile that it’s impossible to locate when wearing gloves.
The UC35 now rides around in my backpack as a waterproof spare cell carrier with a waterproof USB-powered Li-Ion charger built in. It could even serve as a light if I was really stuck.
I too didn’t like the UI with my M43 until I programmed it with the U3 interface. It now has 3 simple modes, and crazy turbo. I programmed it to have moonlight (which is impressively low for this flashlight), medium, and high. And turbo is always accessible by holding the button. But that’s not on topic for this post.
The flashlight that is great, but I hate the most is my Astrolux A01 Nichia 219B. Sure it has great tint, but I hate that it’s a twisty. I understand the design allows it to be very small, but rotating the head to turn it on and change the modes is not easy with this flashlight. I tried cleaning the threads and re-lubing, but it still takes a lot of effort to rotate the head. So much so that my wife gave it back to me and wanted a different flashlight. Now it just sits in a drawer as a back-up.
Any Convoy flashlight (I own three). They are well-built, perform well, have a beautiful finish, and are priced right. But the memory function is backwards to me. I often get the “next” mode by surprise when I turn it back on. I’ll never buy another Convoy until they change it.
OTOH, I love the way that the Solarforce memory function works.
Eagle Eye X6-SE BLF Edition
It’s surely a nice flashlight, but I never got to like it, I think it’s because the battery-tube is too small both in diameter and lenght for me
Luckysun D80
I don’t know, why I don’t like this light - but I know, that I don’t like this light.
Convoy L4
The fact, that it is a 2-switch light and has this ugly ansd non-removable anti-roll-thing on the tail switch is a nono for me.
I changed the driver to one that only needs the side-switch and put a UV LED in it, so it’s an OK light now.
the worst of them all:
Nitecore EC21
One of my more expensive light - and one of my less bright (?) ones.
Never ever used this one really, just because it’s not bright enough and the UI is clunky.
And lights that I don’t own:
Fireflies ROT66
That bare aluminium backpart just kills this light for me, it looks so cheap.
Another vote for the Nitecore Tini, I love the size/weight/lumen ratio, so I put it on my keychain. Used it fore 3 months almost daily, then the buttons started to fail. Had no time to open it up fore someweeks, finally got to it to find out that the battery died.
Love the light but hate the quality, plastic is not the right material for a keychain product.
Still looking for a worthy titanium replacement.
MS12. I don’t own it yet, but i can imagine its greatness and short coming compared to competitors and my experience using many other flashlight.
Great for its 50k output lumens and using 8x20700.
Hate its ineffective fan, difficult to access charging port, holes on bezel, difficult to find switch in the dark.
I wish it’s perfect.
Rovyvon A4 might be the thing for you:
mine is sofirn aaa red pen light. sometime i love it sometime hate . i do not know why? maybe the reason is the color. 
That’s the dreaded 3/5 firmware that I mentioned in my own entry. Your pitfall here is that in its case, it’s ON-time memory, so the light has to stay on for some 3 seconds to memorise the mode you’re using.
Tip: don’t buy Convoy from third parties, go to its own Aliexpress store, and when you purchase one, ask for the new Biscotti firmware on it via PM before paying. You can also buy the drivers separately there to upgrade your torches - I have two coming to slap onto my old S2 and my C8. After you try that, I guarantee you’ll never look at a Convoy sideways by principle again.
Found that one already but haven’t found a way to buy it except via amazon.es for 160 euro