Regular/daily use is definitely demotivational, at least in the long run. This can (but certainly doesn't necessarily) lead to depression, which can be a serious illness for some.
One major effect is that use makes things more interesting. This can be beneficial - it might allow an artist or programmer to dive into their work or help in music appreciation. This same property also masks boredom which can have serious consequences. Someone who is bored with their life often seeks to change it for the better, a person bored with TV may turn it off.
This! If you're watching futurama for the 10th time, you have to wonder if your time might be put to more use elsewhere. It's actually quite funny, not only makes pot stuff more interesting, you also forget a lot of details which makes is much easier to do them again and again and ....
One major effect is that use makes things more interesting. This can be beneficial - it might allow an artist or programmer to dive into their work or help in music appreciation. This same property also masks boredom which can have serious consequences. Someone who is bored with their life often seeks to change it for the better, a person bored with TV may turn it off.