I'm one of those twonks you see blowing huge clouds with a massive battery box, let me explain why and it's not for show... well mostly not...
I smoked heavily for years, got back into the dating game and realised that stinking of fags wasn't helping the chances of a spaghetti arm, neckbeard, IT nerd so decided to give e-cigs a try.
I started on plastic cigalikes, didn't do anything for me, so upgraded to various expensive devices using 18mg liquid. It was horrible, the taste, the mouth ulcers, coughing, spilling liquid on your hands caused you to feel sick for hours, it was a nightmare, so I wandered into my local vape shop and asked what was the next and last option. Subtanks: lower ohm, higher wattage, lower nicotine, less PG which was irritating my chest but more "clouds" as a result. After previously reading up on "the best cigarette-like experience" and following various advice, I discovered I didn't want a lung ripping harsh high nicotine hit like it recommended, I wanted a warm, smooth, thick vapour, I could feel it in my lungs like a cigarette, I could see it when I exhale, it didn't give me mouth ulcers and didn't irritate my throat/chest.
I wasn't huffing on my vape pen like a madman during my break anymore, I would just have a good couple of lungfulls and I was done, the nicotine is only half the problem, I think most people give up on e-cigs as cheap devices offer such a bad experience, I know I didn't get on with them and if it wasn't for me wandering into my local vape shop, I would be back on the cigs.
People take the piss when they see me blowing big clouds, but that's fine, it keeps me off the fags, my 2 year old daughter doesn't say I stink anymore, it saves me money and will (hopefully, if I stop drinking) will add a few years to my life.
Don't dismiss "cloud chasers" as a novelty thing, for some people it is the best solution they have found.