I can relate to your plight because I'm not a fan of either Mentor or Shops. I think the key to 'getting through it' is to take solid personal inventory RE what is important to you about playing Vintage and align it with the reality we are in. Which is more important to you, winning or playing something you like/having fun? That's not to say you can't do both, but there is a decent amount of data to suggest if winning is your key focus, some form of Mentor or Shops should be your deck choice. If you prefer to go against the grain or have a particular pet deck, play that instead, but do so with the knowledge that you are handicapping yourself on potential win percentage. Even this approach can be taken in 2 distinct ways:Bury your head in the sand and play what you love and don't worry about your mentor/shops matchup :) Grixis Vault-Key is my all time favorite vintage deck, and I love to play it, but I would effectively be doing this by sleeving it up Play something not mentor/shops, but make sure your deck has some form of plan against the 2 and try to give thema a run for their money! (again, understanding 'that plan' is likely a weaker option than just playing one of those decks). I've been working on a Deathrite Shaman 4CC list that is firmly tier 2, but I enjoy playing it and it doesn't completely fold to those 2 decks, so I've stayed happy tinkering away with the list. Would I like to win more? Absolutely, but not at the cost of playing Mentor or Shops since neither of those decks appeal to me.
A lot of time is spent on TMD arguing about the meta and B&R changes. Not a lot of time is spent saying "Well, this is the world we live it. Lets make the most out of it by maximizing what is important to us individually". This is not to say that meta/B&R discussions aren't important, but they have a time and a place. Its ok to want changes to be made to Vintage, or to have the belief that something is 'wrong' with Vintage, but that facet of Vintage (which is only a small part) doesn't have to completely consume your focus and warp your feelings about it.