I find them boring too tbh. lmao I hate slice-of-life and romance anime - even My Lie in April, yes. I didn't cry watching MLiA! Sorry to disappoint, folks, but that trope is overplayed. It's like a darn soap opera.
That said, their opening themes though can be nice. The reason I pointed out Angel Beats was because of the use of that piano at the beginning of the theme, the piano which becomes quite an essential element of the plot. That's meaningful use of the music in the anime, and I like that, even though I'm really not a fan of Angel Beats (the anime) at all.
Likewise for My Lie in April. It's amazing how such a depressing anime could have such a happy beat used in such a evocative way, the way the lyrics literally tells you, literally foreshadows the tragedy the characters are trying to overcome. lol
See, I like that kind of creativity in music composing and just creativity in art in general (pretentious as that might sound lol). It's why I appreciate unique OPs that try to do something different with the music, like Elfen Lied (opera singing) and Baccano (jazz music). These are not just good anime OPs; these are great music.