Hobbies aren't a waste of time. Hobbies help you pass time by doing something you're interested in.

Yeah. You're right. Hobbies are a real waste of time. Let me run down my list of hobbies that, due to this opinion, that I am going to put to the wayside.

Sex. HUGE waste of time. Honestly, who wants to spend their time making love to a significant other? Who hates uncovering the mystery of what that significant other has on underneath that blouse? Yeah. No more doing that.

Masturbation. Another waste of time. Who wants to waste their time causing a self-induced orgasm when you fail to find out what is underneath that blouse? No more doing that. I'll just store it all up for when I want to attempt to have children. Brilliant.

Music. No more looking for that one song to fit how I may be feeling at a certain moment. I'll just sit in a dark corner and stew over it.

Hobbies is that which makes our spare time tolerable.

Look up Day 9 Daily on youtube. It's essentially a nerd talking about his favorite video. He did this for a year just for fun. These videos landed him a job as a newscaster for MLG. He was even featured in Forbes. That's a great example of hobbies not being a waste of time. I guess it depends on the hobby and what you consider a waist of time.