"thongar" It's bad if it starts to overtake what you should be doing (e.g. work, study etc), but I don't think it's bad if you have nothing else to do.
Would that "etc." include, oh, I don't know ... actually practicing the ukulele?
I am guilty sometimes that my "practice" time includes a lot of webbernet surfing, but often I find something new and awesome to learn so it's all good.
As a political junkie and uke lover I spent about two hours last night practicing a finger-picking song while watching the political speeches (we have a little election-thingy coming up soon here in the USofA).
So two hours of +
but I made good progress and hope to share the song with y'alls soon!