Travelling solo: Hotel vs. Hostel

I have traveled alone before and I have enjoyed it, but had the occasional bout of loneliness. I am looking to travel some more, and I'm not sure whether to stay in a hotel or a hostel. I've read online that staying in a hostel makes it much easier to meet other travelers and make friends. However, my style of travelling is usually to wake early, spend the whole day sightseeing/hiking, get back to the hotel and go to sleep early in preparation for the next day. I've never stayed in a hostel before, but something tells me that really won't be an option (I just natrually assume all hostels are like the one Karl Pilkington stayed at in Rio).

Other stuff:

* I am a young female, so safety is somewhat of an issue * I'm not going for a long-haul trip, probably several 3 or 4 night stays here and there * I will be travelling mostly in continental Europe

So I'm wondering what r/travel's experiences have been with hostels, and if you have any tips on staying in one!