I just think they are the sort of questions that are never asked in life, that you'd need to revise for, and would just make me look a fool
Well... they can be a bit weird, but they're about aptitude, not knowledge. You can definitely get better at the tests by practicing, especially if they make you uncomfortable. A lot of tests seem like they are nothing to with life but they actually are - for example, some of the weird geometrical ones test how well you'll do fitting complicated shapes together, especially when you have to rotate pieces, so they're very relevant to bike repair.
However, some people are a lot better thinking about definite, practical cases rather than abstract problems, and this hurts test results. Often these people can get a lot better with some practice because they learn to just thinking "This is silly and weird!"