It's probably observation bias or coincidence but lately I've noticed enough questions without upvotes but plenty of answers (or at least one answer) to bother me. In fact, I first noticed it on a question that I answered myself but forgot to upvote.
If a question is worth answering it is usually (not always) good enough to deserve an upvote, so please remember to also upvote a question if you find it interesting enough to answer.