Its worth it spending more days in London. Fun place to be with. Try one of those hop on and off bus tours for a day which would give you a good idea on london.
Try some of the london pubs or the great Indian restaurants or walk around Trafalgar or Covent Gardens…Lots of things to do and see……

What’s the name of the “hop on and off” tours? I saw them mentioned in another thread. Do you have to book tickets, or do you literally just go to a stop, hop on, and get off where you want? Do they take circular routes or do they involve planning?

I should also add that I’ll be alone there. I should probably manage to make some acquantices at the hostel and go out to a bar at night…any areas/place I should avoid, or recommended bars? And for that matter, what’s the difference between pubs and bars in London? In my city they are mostly the same, though some pubs have a dance area and serve a bit more than alcohol (like..fries, popcorn).

The name of one of the hop-on hop-off tours is ‘Big Bus’, you purchase the ticket on the bus and they are valid for 24 hours, so if you get the ticket at midday, it is valid until miday the next day, you also get a free boat ride on the Thames.
A pub is where anyone and everyone drinks, they serve good wholesome food and more relaxing, whereas a bar is more upmarket (so I recon) and serve more types of wines and a upmarket sandwhich type of food

I think 1 or 2 hours in Lomdon is too much

I love London, it’s just so expensive.  But if it’s your first time there, then go for the 2 days.  Otherwise, save some money.

2 days
and all the great museums are free

If you’re into museums, you could spend far more than a day in the British Museum. If you’re into pubs, the number of options is immense.

I think one day in London was too little time for you to experience and discover the beauty of cans don.