bleach said:
Then the TV eventually turns off on its own, and nothing you did mattered anyway.
I used to feel this way too, especially after someone very close to me died, but over the past few years I've come to feel that each individual moment is as important as the next. It's hard to explain without it sounding cliched, but I really believe that living for the moment is the best way to appreciate our lives and experience all that we can from them.
Why should the fact that we'll cease to exist one day negate all of our experiences and achievements? People tend to obsess over capturing and storing every part of their lives, recording everything with photos and diaries and videos, but if I were to go on a holiday and see amazing sights, meet interesting people etc, would my experiences cease to matter if they weren't recorded for posterity? Would a grisly murder or heroic act have no impact on the world if it were left out of the history books and eventually forgotten?
Life is transient and this makes us nostalgic for the past and fearful of the future. It seems like we don't spend much time in the present, appreciating our surroundings and enjoying the moment. Think of the times you've spent a special day (Christmas as a kid, trips to exciting places etc) checking the time and bemoaning the fact that it's nearly over rather than just having fun - and this really applies to all of life.
Sorry if this sounds a bit ranty, it's just something that I feel strongly about and I've never actually voiced (or written) these thoughts before, though it's been churning in my head for a while! This isn't at all an attack on what bleach wrote, and I can definitely sympathise with how s/he feels.
EDIT: I've just realised that I didn't answer the original question, sorry! Yes, I think about suicide a lot, despite everything I've written above.