1) Because you're nice. Nice people don't finish last. Maybe in high school this was the case, but in the grown-up real world, nice people will definitely have more chances of finding and staying in good relationships. No one wants to date an a-hole or a b*tch, so stop trying to be one, karma will bite you in the ass.
2) Because you don't have an "amazing" job". A good person will love you for the person you are, not for your job title. And if that is what they care about, you can tell them to buy a one-way ticket to the island of "forever alone because I'm shallow".
3) Because you don't have the "perfect" body. First, the perfect body does not exist because it is completely subjective, meaning everyone has a different definition of what the perfect body is. Second, that means that for some you DO have the perfect body. Third, everyone is attracted to different things, and it's definitely not only about physical attraction.
4) Because you have sex on the first date or don't have sex on the first date. The person you're dating is either in it for sex or in it for a relationship, and what can you do about that? NOTHING! So whether you have sex right away or after 3 dates, the person will be getting the f*ck out regardless. You being single has nothing to do with WHEN you sleep with people, but rather WHO you sleep with.
5) Because you're using dating apps/websites. Ok so yes unfortunately a lot of people seem to be using these just to get laid, but if I personally know around 8 people, including myself, who have had successful relationships from online dating, I don't think the odds are so bad after all.
6) Because you're not a fan of bars or clubs. Actually I think this will increase your chances of finding a relationship rather than finding one-night-stands.
7) Because you have quirks. Everyone does, you'll find someone just as weird as you soon enough don't worry.
8) Because you have no clue what your "5-year plan" is. Technically, no one does unless they're a legit fortune teller and sorry but I don't believe in that sh*t. It's cool to have a plan and all but it's also cool to realize that a lot of things can change in 5 years and you may just not know what exactly you're going to do with your life.
9) Because you want a relationship and aren't afraid to say it. You may think you're scaring people away, but actually you're scaring the wrong people away and you should be happy about that. Someone who is seriously looking for a relationship will appreciate you saying that and won't run away like a little child.
10) Because of your age. Definitely not a reason why you're single..
11) Because you don't have the nicest clothes, shoes, accessories etc. All material things do not impress someone, unless they're a gold digger. It's your personality, manners, and connection that matters, not your brand name sh*t.
12) Because you enjoy your alone time. It's totally fine to be a bit more introverted or simply enjoy doing your own things alone.
13) Because of your personality. I don't care how bossy you are, how lazy you are, or how neurotic you are, there is definitely someone out there whose personality is a good match to yours.