This question already has an answer here:
When I went to Turkey, I was warned that my beard would make police think I was a member of a group that is "not popular" with the authorities. So I removed it. I was glad I did, because in Amsterdam, they spent about three minutes comparing my face to the photo (the photo was taken before I let the beard grow, so it was actually a good match IMHO).
But two years later, the beard is back on the face but still not in the passport. I brush it out, but it still tends to look like the clowns on Duck Dynasty. Is that likely to cause a problem entering U.K. or Spain? I do have driver licenses (Oklahoma and international) that show the beard.
I'd reference a related question but I can't figure out how to do that in the IOS app. Someone has done it for me in the comments. The behavior he described is how the guy in Amsterdam behaved when I DID look like my picture. That's why I wonder if I should shave. It's the British Border Force and the Spanish people that I will have to deal with next week.