Playing games on a mobile phone can be both addictive and time wasting, but it is proven that some games develop the strategic part of your brain so they are not all that bad. Not all elevate your intelligence, but why to bother.
Anyway, you can't actually carry around the whole PlayStation or your gaming PC to enjoy the full sensory experience, it is just not all that practical.
Also if you are at the job, this could get you in trouble, even if it is some light card game or something dumb like answering the notification. If you suffer from the insomnia or getting in bed became a trouble for you, a game that is too exciting can be a bad choice for late evening hours.
So you need something that can go on your smartphone, doesn't waste much space because you need all that for smarter things, can help you out in elevating your strategic capabilities, is not exciting too much and you will not wish to play it for too long?
I suggest you to try either Connection or Connect'em. The both games work on the same principle, you connect dots in a way that rules advise you.
Both games are interesting in small dosage and it will not cause you hours of playing because they will make you feel tired rather quickly. Usually people find them boring enough not to be addicted enough but still interesting enough to trouble with them.