Why are imines bad?

What are the most popular "objectionable" patterns, and why?

Here is a snapshot (out of 100M) thus final numbers might be 2X

  count  | pattern_id |            name             
---------+------------+-----------------------------
 1442785 |         35 | imines
 1081572 |         30 | acylhydrazides
  691034 |          5 | alkyl-halide
  631399 |         33 | propenals
  302056 |         34 | acrylonitriles
  163921 |        497 | anil_di_alk_d_198_
  137175 |          7 | heptanes
  130644 |        494 | ene_rhod_a_235_
   91754 |        489 | azo_a_324_
   77525 |          1 | aliphatic-aldehyde
   72539 |          2 | aliphatic-thiol
   64479 |        493 | anil_di_alk_c_246_
   62752 |        488 | quinone_a_370_
   46270 |        513 | anil_alk_ene_51_
   45002 |         32 | quarternary-n
   38529 |         36 | aminooxy_oxo_
   38155 |         31 | beta-carbonyl-quarternary-n
   37068 |        492 | anil_di_alk_b_251_
   31645 |          4 | acid-halide
   28266 |        498 | imine_one_isatin_189_
   26002 |        490 | imine_one_a_321_
   23183 |         21 | sulfonates
   22046 |        496 | ene_five_het_a_201_
   19426 |        503 | ene_five_het_b_90_
   19134 |          9 | teflon
   18999 |         37 | disulfide
   17194 |         13 | iso_thio_cyanate
   15303 |         12 | peroxide
   13624 |        548 | ene_one_hal_17_
   11896 |         26 | lawssons-reagent
    8571 |        507 | keto_keto_beta_a_68_
    8409 |         16 | p-s-halides
    7965 |        505 | ene_five_het_c_85_
    7261 |         29 | quarts
    6686 |         11 | acid-anhydride
    6572 |        515 | ene_five_het_d_46_
    6114 |        760 | quinone_d_2_
    5742 |        509 | ene_one_ene_a_57_
    5715 |        528 | rhod_sat_a_33_
    5668 |          6 | phosphenes