There are many types of addictions one may have. Unfortunately it could be too well known smoking, alcohol and drugs. Besides these there could be sexual addiction (anyone?), music, computer games, internet, computer in general, long sitting in "beis a-kisei" and others.
From noted here I can highlight two as I am highly addicted to them - music and computer in general.
I always start from the end - especially magazines and books are most interesting in the end. I'll start from the second here too.
If I wasn't addicted I would be simply in the bed for the past two hours. I just can't live without computer. I can't concentrate if I don't sit by it for few minutes. There are times when I tell myself I'm done with work for today or no work today at all but I still get back to the screen every few minutes.
While looking up a link to my comment, i've noticed a relevant topic about life without technology.
Another addiction I mentioned is music. This is not a big deal on regular days - it's just almost 24/6 me listening to music would that be in my earphones or blasting so it's sounds well in the whole apartment. You could hardly see me outside without headphones - it helps me turn from surrounding world and bring some peace to my mind. I listen to music when I program - it helps me concentrate. I listen to music as a noise canceler in the train so I can sleep. I listen to music when I'm depressed and when I'm in a good mood.
These days are hard since it's sfira time when it's customary not to listen to music. There people who say you can listen to recorded music but I hardly accept these leniences. However it doesn't stop me from giving up sometimes and turning on something. Every year it's different (read my comment to get more details on previous years so i don't have to repeat myself). This year it's a choice of only listening to when it's really depressing or when I really need to concentrate on work. Either way it's only part of my playlist which contains depressive music and nothing happy; plus it could not go loud meaning that I would hear anyone talking to me when I wear both headphones.
So yesterday I was having really hard time on concentrating on my work and I turned on music. First it was a set of Eminem (just few songs) but soon it was switched to Dark Tranquility album "The Mind's I" - something I was rarely listening to unless it was in a random play of my entire iPhone playlist. Few hours later I realized that although this music did really help me to concentrate I can't recall most of what I was listening to - i.e. it was just making a comfortable background that didn't not bother me but at the same time it didn't get my attention. Something nearly perfect.
Something I was noticing before too but this time I made me think again on it's meaning - most of the time I don't listen to the music. I breath it. Like we don't notice how we breath i listen to music, but if we stop breathing we'd die - same if i stop music I'm not feeling comfortable anymore.