Does my 8 month old cat want a companion?

I originally thought my cat wanted to be an only cat. Anytime we would take her over to my in-laws to play with their cats barely younger than her she would hiss and would NOT want us to touch her. But normally by the end of the visit she acted interested in the cats and even wanted to play. We went out of town last week and they kept her at their house for 4 nights. By the time we came back her attitude towards the other cats had changed drastically and she enjoyed their company. Now since bringing her home she has acted a little differently. I wonder if she is bored? There are times when she just wants to be alone and sleep but as I type this she's trying to entertain herself with a little stick. Since the vacation, she'll now just look at me and meow like she wants something but she has food and everything. Should we get her a playmate?

Cats will normally hiss at other cats in the beginning, they are not friendly towards each other like dogs. Your cat got used to the other cats and that is why she got better with them. She might enjoy another cat, most females are prima donnas, so a neutered male would be a good match, I would get one a little younger then yours. Usually it takes a lot of separation and 'introducing' to get cats to get along, you've been lucky so far. Good luck and keep us posted!

Just to echo what Di and Bob has said; the hissing is normal for cats.  Being territorial; they need to be introduced to each other.  Cats who enjoy "play dates" are more the exception than the rule.  It sounds like she accepted being with the other cats fairly well if she was doing well after only 4 days!  Some cats take MONTHS to integrate.  I do think it can help when the cats are younger or still kittens.  She may take things a bit harder when she is the one having someone new come into her territory.

I have only had 1 male cat in my lifetime and he was brought home as a tiny kitten; so I don't have experience with them being easier to integrate.  I have had adult females accept each other; but this was 20 years ago and before I knew that there are proper/recommended techniques to help this along.  

This article explains the introduction methods we usually recommend: http://www.thecatsite.com/a/introducing-cats-to-cats  You may find things can move along a little faster; or you might have to be patient.  My experience is that 2 young cats are way easier than 1 young cat and they do enjoy having a playmate. 

Just to update... We did end up getting a male kitten and they are great friends! They play all the time and enjoy each other's company. We did not use any specific introduction method. I know, shame on us. I felt like with my female cat's personality it would have just drug out the process like in a "Does this cat live with us or not?" kind of way. Lol.. So anyway.. I'm very glad we chose to get her a playmate!