Names are one of the cornerstones of genealogy and family history - it's our main jumping off point for what we do. They are what we search by most of the time, and they are what we put on pedigree charts. I find first names particularly interesting - some people have them passed through families (for example, using the Scottish naming pattern), and some are unique; and some are downright misleading. First names can trip you up so many times in your research - and I have many examples from my own research.
1. Girls given what we would consider a male name
My partner's 4 x great grandmother was a woman named Stewart McCreadie. There is no typing error here - that genuinely was her name. The first time I saw it written on a record, the handwriting was quite difficult and I transcribed it as Margaret. But on a second record, it was very clear. Similarly, my grandmother's closest friend as a child was a girl called Gordon.
The name Christian is now considered a male name, but in Scotland it was used as a name for girls. It is sometimes interchangeable with Christina. My 4 x great grandmother was called Christian and is sometimes listed as Christina, but just to add some interest, it is occasionally Catherine/Katherine.
Following on from point 1, some Scottish families give their daughters traditionally male names and add -ina to the end to feminise it a little. Most people are quite familiar with some instances of this - Georgina or Thomasina for example. But there are some more unusual ones out there. I've seen Donaldina, Neilina and Giffordina in my own research. Unusual names by themselves can often make researching easier - the problem arises when the name is just shortened to Ina, and you don't know what, if anything, it is shortened from.
3. Unusual variations
I think most people are used to the myriad variations around Jean, Jane, Janet and Jessie - not to mention Jennet. Similarly for Margaret (Maggie, Peggy, Meg) - but my grandmother, Margaret, was always known as Greta. My 5 x great grandmother (Christian's mother) appears mostly in records as Isabel or Isabella, but there is at least one instance of her being called Elizabeth. While it looks wrong, the two names come from the same root and were interchangeable in the past.
4. People their middle name as a first name
My friend and his father share the same first name, but neither of them uses it - both use their middle names. My partner's grandfather also used his middle name. This has tripped me up a couple of times on certificates where the commonly used name is given rather than the 'correct' first name.
It can be very easy to completely discount a record if a first name doesn't match, but it can pay to keep your wits about you. I've been reviewing my old research recently - some parts of it I hadn't looked at for more than ten years, and I've made some progress on branches purely around name variations I wasn't aware of when I was starting out.